Measuring change in trials of physical activity interventions: a comparison of self-report questionnaire and accelerometry within the PACE-UP trial.

BACKGROUND: Few trials have compared estimates of change in physical activity (PA) levels using self-reported and objective PA measures when evaluating trial outcomes. The PACE-UP trial offered the opportunity to assess this, using the self-administered International Physical Activity Questionnaire (IPAQ) and waist-worn accelerometry. METHODS: The PACE-UP trial (N = 1023) compared usual care (n = 338) with two pedometer-based walking interventions, by post (n = 339) or with nurse support (n = 346). Participants wore an accelerometer at baseline and 12 months and completed IPAQ for the same 7-day periods. Main outcomes were weekly minutes, all in ≥10 min bouts as per UK PA guidelines of: i) accelerometer moderate-to-vigorous PA (Acc-MVPA) ii) IPAQ moderate+vigorous PA (IPAQ-MVPA) and iii) IPAQ walking (IPAQ-Walk). For each outcome, 12 month values were regressed on baseline to estimate change. RESULTS: Analyses were restricted to 655 (64%) participants who provided data on all outcomes at baseline and 12 months. Both intervention groups significantly increased their accelerometry MVPA minutes/week compared with control: postal group 42 (95% CI 22, 61), nurse group 43 (95% CI 24, 63). IPAQ-Walk minutes/week also increased: postal 57 (95% CI 2, 112), nurse 43 (95% CI -11, 97) but IPAQ-MVPA minutes/week showed non-significant decreases: postal -11 (95% CI -65, 42), nurse -34 (95% CI -87, 19). CONCLUSIONS: Our results demonstrate the necessity of using a questionnaire focussing on the activities being altered, as with IPAQ-Walk questions. Even then, the change in PA was estimated with far less precision than with accelerometry. Accelerometry is preferred to self-report measurement, minimising bias and improving precision when assessing effects of a walking intervention. TRIAL REGISTRATION: ISRCTN, ISRCTN98538934 . Registered 2 March 2012.

Physical activity levels in adults and older adults 3-4 years after pedometer-based walking interventions: Long-term follow-up of participants from two randomised controlled trials in UK primary care.

BACKGROUND: Physical inactivity is an important cause of noncommunicable diseases. Interventions can increase short-term physical activity (PA), but health benefits require maintenance. Few interventions have evaluated PA objectively beyond 12 months. We followed up two pedometer interventions with positive 12-month effects to examine objective PA levels at 3-4 years. METHODS AND FINDINGS: Long-term follow-up of two completed trials: Pedometer And Consultation Evaluation-UP (PACE-UP) 3-arm (postal, nurse support, control) at 3 years and Pedometer Accelerometer Consultation Evaluation-Lift (PACE-Lift) 2-arm (nurse support, control) at 4 years post-baseline. Randomly selected patients from 10 United Kingdom primary care practices were recruited (PACE-UP: 45-75 years, PACE-Lift: 60-75 years). Intervention arms received 12-week walking programmes (pedometer, handbooks, PA diaries) postally (PACE-UP) or with nurse support (PACE-UP, PACE-Lift). Main outcomes were changes in 7-day accelerometer average daily step counts and weekly time in moderate-to-vigorous PA (MVPA) in ≥10-minute bouts in intervention versus control groups, between baseline and 3 years (PACE-UP) and 4 years (PACE-Lift). PACE-UP 3-year follow-up was 67% (681/1,023) (mean age: 59, 64% female), and PACE-Lift 4-year follow-up was 76% (225/298) (mean age: 67, 53% female). PACE-UP 3-year intervention versus control comparisons were as follows: additional steps/day postal +627 (95% CI: 198-1,056), p = 0.004, nurse +670 (95% CI: 237-1,102), p = 0.002; total weekly MVPA in bouts (minutes/week) postal +28 (95% CI: 7-49), p = 0.009, nurse +24 (95% CI: 3-45), p = 0.03. PACE-Lift 4-year intervention versus control comparisons were: +407 (95% CI: -177-992), p = 0.17 steps/day, and +32 (95% CI: 5-60), p = 0.02 minutes/week MVPA in bouts. Neither trial showed sedentary or wear-time differences. Main study limitation was incomplete follow-up; however, results were robust to missing data sensitivity analyses. CONCLUSIONS: Intervention participants followed up from both trials demonstrated higher levels of objectively measured PA at 3-4 years than controls, similar to previously reported 12-month trial effects. Pedometer interventions, delivered by post or with nurse support, can help address the public health physical inactivity challenge. TRIAL REGISTRATIONS: PACE-UP isrctn.com ISRCTN98538934; PACE-Lift isrctn.com ISRCTN42122561.

Interpreting population reach of a large, successful physical activity trial delivered through primary care.

BACKGROUND: Failure to include socio-economically deprived or ethnic minority groups in physical activity (PA) trials may limit representativeness and could lead to implementation of interventions that then increase health inequalities. Randomised intervention trials often have low recruitment rates and rarely assess recruitment bias. A previous trial by the same team using similar methods recruited 30% of the eligible population but was in an affluent setting with few non-white residents and was limited to those over 60 years of age. METHODS: PACE-UP is a large, effective, population-based walking trial in inactive 45-75 year-olds that recruited through seven London general practices. Anonymised practice demographic data were available for all those invited, enabling investigation of inequalities in trial recruitment. Non-participants were invited to complete a questionnaire. RESULTS: From 10,927 postal invitations, 1150 (10.5%) completed baseline assessment. Participation rate ratios (95% CI), adjusted for age and gender as appropriate, were lower in men 0.59 (0.52, 0.67) than women, in those under 55 compared with those ≥65, 0.60 (0.51, 0.71), in the most deprived quintile compared with the least deprived 0.52 (0.39, 0.70) and in Asian individuals compared with whites 0.62 (0.50, 0.76). Black individuals were equally likely to participate as white individuals. Participation was also associated with having a co-morbidity or some degree of health limitation. The most common reasons for non-participation were considering themselves as being too active or lack of time. CONCLUSIONS: Conducting the trial in this diverse setting reduced overall response, with lower response in socio-economically deprived and Asian sub-groups. Trials with greater reach are likely to be more expensive in terms of recruitment and gains in generalizability need to be balanced with greater costs. Differential uptake of successful trial interventions may increase inequalities in PA levels and should be monitored. TRIAL REGISTRATION: ISRCTN.com ISRCTN98538934 . Registered 2nd March 2012.

Effect of a Primary Care Walking Intervention with and without Nurse Support on Physical Activity Levels in 45- to 75-Year-Olds: The Pedometer And Consultation Evaluation (PACE-UP) Cluster Randomised Clinical Trial.

BACKGROUND: Pedometers can increase walking and moderate-to-vigorous physical activity (MVPA) levels, but their effectiveness with or without support has not been rigorously evaluated. We assessed the effectiveness of a pedometer-based walking intervention in predominantly inactive adults, delivered by post or through primary care nurse-supported physical activity (PA) consultations. METHODS AND FINDINGS: A parallel three-arm cluster randomised trial was randomised by household, with 12-mo follow-up, in seven London, United Kingdom, primary care practices. Eleven thousand fifteen randomly selected patients aged 45-75 y without PA contraindications were invited. Five hundred forty-eight self-reporting achieving PA guidelines were excluded. One thousand twenty-three people from 922 households were randomised between 2012-2013 to one of the following groups: usual care (n = 338); postal pedometer intervention (n = 339); and nurse-supported pedometer intervention (n = 346). Of these, 956 participants (93%) provided outcome data (usual care n = 323, postal n = 312, nurse-supported n = 321). Both intervention groups received pedometers, 12-wk walking programmes, and PA diaries. The nurse group was offered three PA consultations. Primary and main secondary outcomes were changes from baseline to 12 mo in average daily step-counts and time in MVPA (in ≥10-min bouts), respectively, measured objectively by accelerometry. Only statisticians were masked to group. Analysis was by intention-to-treat. Average baseline daily step-count was 7,479 (standard deviation [s.d.] 2,671), and average time in MVPA bouts was 94 (s.d. 102) min/wk. At 12 mo, mean steps/d, with s.d. in parentheses, were as follows: control 7,246 (2,671); postal 8,010 (2,922); and nurse support 8,131 (3,228). PA increased in both intervention groups compared with the control group; additional steps/d were 642 for postal (95% CI 329-955) and 677 for nurse support (95% CI 365-989); additional MVPA in bouts (min/wk) were 33 for postal (95% CI 17-49) and 35 for nurse support (95% CI 19-51). There were no significant differences between the two interventions at 12 mo. The 10% (1,023/10,467) recruitment rate was a study limitation. CONCLUSIONS: A primary care pedometer-based walking intervention in predominantly inactive 45- to 75-y-olds increased step-counts by about one-tenth and time in MVPA in bouts by about one-third. Nurse and postal delivery achieved similar 12-mo PA outcomes. A primary care pedometer intervention delivered by post or with minimal support could help address the public health physical inactivity challenge. CLINICAL TRIAL REGISTRATION: isrctn.com ISRCTN98538934.

Self-monitoring of blood pressure in hypertension: A systematic review and individual patient data meta-analysis.

BACKGROUND: Self-monitoring of blood pressure (BP) appears to reduce BP in hypertension but important questions remain regarding effective implementation and which groups may benefit most. This individual patient data (IPD) meta-analysis was performed to better understand the effectiveness of BP self-monitoring to lower BP and control hypertension. METHODS AND FINDINGS: Medline, Embase, and the Cochrane Library were searched for randomised trials comparing self-monitoring to no self-monitoring in hypertensive patients (June 2016). Two reviewers independently assessed articles for eligibility and the authors of eligible trials were approached requesting IPD. Of 2,846 articles in the initial search, 36 were eligible. IPD were provided from 25 trials, including 1 unpublished study. Data for the primary outcomes-change in mean clinic or ambulatory BP and proportion controlled below target at 12 months-were available from 15/19 possible studies (7,138/8,292 [86%] of randomised participants). Overall, self-monitoring was associated with reduced clinic systolic blood pressure (sBP) compared to usual care at 12 months (-3.2 mmHg, [95% CI -4.9, -1.6 mmHg]). However, this effect was strongly influenced by the intensity of co-intervention ranging from no effect with self-monitoring alone (-1.0 mmHg [-3.3, 1.2]), to a 6.1 mmHg (-9.0, -3.2) reduction when monitoring was combined with intensive support. Self-monitoring was most effective in those with fewer antihypertensive medications and higher baseline sBP up to 170 mmHg. No differences in efficacy were seen by sex or by most comorbidities. Ambulatory BP data at 12 months were available from 4 trials (1,478 patients), which assessed self-monitoring with little or no co-intervention. There was no association between self-monitoring and either lower clinic or ambulatory sBP in this group (clinic -0.2 mmHg [-2.2, 1.8]; ambulatory 1.1 mmHg [-0.3, 2.5]). Results for diastolic blood pressure (dBP) were similar. The main limitation of this work was that significant heterogeneity remained. This was at least in part due to different inclusion criteria, self-monitoring regimes, and target BPs in included studies. CONCLUSIONS: Self-monitoring alone is not associated with lower BP or better control, but in conjunction with co-interventions (including systematic medication titration by doctors, pharmacists, or patients; education; or lifestyle counselling) leads to clinically significant BP reduction which persists for at least 12 months. The implementation of self-monitoring in hypertension should be accompanied by such co-interventions.

Which sexually active young female students are most at risk of pelvic inflammatory disease? A prospective study.

OBJECTIVE: To identify risk factors for pelvic inflammatory disease (PID) in female students. METHODS: We performed a prospective study set in 11 universities and 9 further education colleges in London. In 2004-2006, 2529 sexually experienced, multiethnic, female students, mean age 20.8 years, provided self-taken vaginal samples and completed questionnaires at recruitment to the Prevention of Pelvic Infection chlamydia screening trial. After 12 months, they were followed up by questionnaire backed by medical record search and assessed for PID by blinded genitourinary medicine physicians. RESULTS: Of 2004 (79%) participants who reported numbers of sexual partners during follow-up, 32 (1.6%, 95% CI 1.1% to 2.2%) were diagnosed with PID. The strongest predictor of PID was baseline Chlamydia trachomatis (relative risk (RR) 5.7, 95% CI 2.6 to 15.6). After adjustment for baseline C. trachomatis, significant predictors of PID were ≥2 sexual partners or a new sexual partner during follow-up (RR 4.0, 95% CI 1.8 to 8.5; RR 2.8, 95% CI 1.3 to 6.3), age <20 years (RR 3.3, 95% CI 1.5 to 7.0), recruitment from a further education college rather than a university (RR 2.6, 95% CI 1.3 to 5.3) and history at baseline of vaginal discharge (RR 2.7, 95% CI 1.2 to 5.8) or pelvic pain (RR 4.1, 95% CI 2.0 to 8.3) in the previous six months. Bacterial vaginosis and Mycoplasma genitalium infection were no longer significantly associated with PID after adjustment for baseline C. trachomatis. CONCLUSIONS: Multiple or new partners in the last 12 months, age <20 years and attending a further education college rather than a university were risk factors for PID after adjustment for baseline C. trachomatis infection. Sexual health education and screening programmes could be targeted at these high-risk groups. TRIAL REGISTRATION NUMBER: (ClinicalTrials.gov NCT00115388).

A primary care nurse-delivered walking intervention in older adults: PACE (pedometer accelerometer consultation evaluation)-Lift cluster randomised controlled trial.

BACKGROUND: Brisk walking in older people can increase step-counts and moderate to vigorous intensity physical activity (MVPA) in ≥10-minute bouts, as advised in World Health Organization guidelines. Previous interventions have reported step-count increases, but not change in objectively measured MVPA in older people. We assessed whether a primary care nurse-delivered complex intervention increased objectively measured step-counts and MVPA. METHODS AND FINDINGS: A total of 988 60-75 year olds, able to increase walking and randomly selected from three UK family practices, were invited to participate in a parallel two-arm cluster randomised trial; randomisation was by household. Two-hundred-ninety-eight people from 250 households were randomised between 2011 and 2012; 150 individuals to the intervention group, 148 to the usual care control group. Intervention participants received four primary care nurse physical activity (PA) consultations over 3 months, incorporating behaviour change techniques, pedometer step-count and accelerometer PA intensity feedback, and an individual PA diary and plan. Assessors were not blinded to group status, but statistical analyses were conducted blind. The primary outcome was change in accelerometry assessed average daily step-counts between baseline and 3 months, with change at 12 months a secondary outcome. Other secondary outcomes were change from baseline in time in MVPA weekly in ≥10-minute bouts, accelerometer counts, and counts/minute at 3 months and 12 months. Other outcomes were adverse events, anthropometric measures, mood, and pain. Qualitative evaluations of intervention participants and practice nurses assessed the intervention's acceptability. At 3 months, eight participants had withdrawn or were lost to follow-up, 280 (94%) individuals provided primary outcome data. At 3 months changes in both average daily step-counts and weekly MVPA in ≥10-minute bouts were significantly higher in the intervention than control group: by 1,037 (95% CI 513-1,560) steps/day and 63 (95% CI 40-87) minutes/week, respectively. At 12 months corresponding differences were 609 (95% CI 104-1,115) steps/day and 40 (95% CI 17-63) minutes/week. Counts and counts/minute showed similar effects to steps and MVPA. Adverse events, anthropometry, mood, and pain were similar in the two groups. Participants and practice nurses found the intervention acceptable and enjoyable. CONCLUSIONS: The PACE-Lift trial increased both step-counts and objectively measured MVPA in ≥10-minute bouts in 60-75 year olds at 3 and 12 months, with no effect on adverse events. To our knowledge, this is the first trial in this age group to demonstrate objective MVPA increases and highlights the value of individualised support incorporating objective PA assessment in a primary care setting. TRIAL REGISTRATION: Controlled-Trials.com ISRCTN42122561.

Evaluation of a specialist nurse-led hypertension clinic with consultant backup in two inner city general practices: randomized controlled trial.

BACKGROUND: Although practice nurses are increasingly involved in hypertension management, there is little robust evidence of effectiveness. OBJECTIVE: To evaluate the effect of a specialist nurse-led hypertension clinic with consultant backup on change in systolic blood pressure. DESIGN: Randomized trial. SETTING: Two inner city general practices. Participants. Three hundred and fifty-three patients, mean age 62 years (range 18-99), with last recorded blood pressure ≥ British Hypertension Society audit standard were randomly allocated to the nurse-led clinic or usual care. Intervention. Patients received a letter informing them that their last blood pressure was over target and inviting them to the clinic. After assessment at the clinic, the nurse discussed any changes in anti-hypertensive treatment with a visiting consultant and the patient's GP, and followed up the patient over 6 months until blood pressure targets were achieved. MAIN OUTCOME MEASURE: Reduction in systolic blood pressure, assessed using two audits of the practices' computerized records where blood pressure was measured independently by practice staff before and after the intervention period. RESULTS: Follow-up was 89% (313/353). There was greater reduction in systolic blood pressure in the clinic group (n = 144) than usual care group (n = 169, adjusted difference 4.4 mmHg; 95% CI 0.7 to 8.2). Of 167 patients randomly selected for the clinic, 91 (55%) attended, 49 had blood pressure above target when measured according to protocol and 26 had their anti-hypertensive treatment intensified by their GP. CONCLUSION: Invitation to a specialist nurse-led hypertension clinic with consultant back up was associated with reduced systolic blood pressure.

Home blood pressure monitoring with nurse-led telephone support among patients with hypertension and a history of stroke: a community-based randomized controlled trial.

BACKGROUND: Adequate control of blood pressure reduces the risk of recurrent stroke. We conducted a randomized controlled study to determine whether home blood pressure monitoring with nurse-led telephone support would reduce blood pressure in patients with hypertension and a history of stroke. METHODS: We recruited 381 participants (mean age 72 years) from outpatient and inpatient stroke clinics between Mar. 1, 2007, and Aug. 31, 2009. Nearly half (45%, 170) of the participants had some disability due to stroke. Participants were visited at home for a baseline assessment and randomly allocated to home blood pressure monitoring (n = 187) or usual care (n = 194). Those in the intervention group were given a monitor, brief training and telephone support. Participants who had home blood pressure readings consistently over target (target < 130/80 mm Hg) were advised to consult their family physician. The main outcome measure was a fall in systolic blood pressure after 12 months, measured by an independent researcher unaware of group allocation. RESULTS: Despite more patients in the intervention group than in the control group having changes to antihypertensive treatment during the trial period (60.1% [98/163] v. 47.6% [78/164], p = 0.02), the fall in systolic blood pressure from baseline did not differ significantly between the groups (adjusted mean difference 0.3 mm Hg, 95% confidence interval -3.6 to 4.2 mm Hg). Subgroup analysis showed significant interaction with disability due to stroke (p = 0.03 at 6 months) and baseline blood pressure (p = 0.03 at 12 months). INTERPRETATION: Overall, home monitoring did not improve blood pressure control in patients with hypertension and a history of stroke. It was associated with a fall in systolic pressure in patients who had uncontrolled blood pressure at baseline and those without disability due to stroke. TRIAL REGISTRATION: ClinicalTrials.gov registration NCT00514800.

Home blood pressure monitoring in hypertensive stroke patients: a prospective cohort study following a randomized controlled trial.

BACKGROUND: We found little data on long-term home blood pressure monitoring in stroke patients. OBJECTIVES: After completing a 12-month trial of home monitoring in hypertensive stroke patients, we investigated the following: 1. The proportion of 118 control patients offered a monitor at the end of the trial without nurse support who used it at least monthly after 6 months. 2. The proportion of 119 intervention patients continuing to use their monitor monthly after 18 months. 3. Possible predictors of monitoring weekly in the first month after receiving a monitor: age, gender, ethnicity, cognition, anxiety, disability, ability to monitor blood pressure unaided and smoking. METHODS: Participants (mean age 71, 34% with disability and 21% from ethnic minorities) were surveyed 1 and/or 6 months after the trial ended by postal and/or telephone questionnaire. RESULTS: Of 237 potential participants, 53 (22%) declined, 16 (6%) were lost and 9 (4%) died during follow-up. Overall, reported monthly use of the monitor without nurse support was 47% [54/114, 95% confidence interval (CI) 38.2-56.5] at 6 months and 50% (57/114, 95% CI 40.8-59.2) at 18 months. Participants who monitored weekly after 1 month were more likely than the remainder to have no disability [Rankin score ≤ 1; relative risk (RR) 1.2; 95% CI 1.0-1.5] and low anxiety levels (FEAR score = 0; RR 1.5; 95% CI 1.1-2.0). CONCLUSION: Around half of hypertensive stroke patients offered a blood pressure monitor but no support continued to use it after 6 and 18 months. Monitoring in the first month was common in those who were not anxious or disabled.

How reliable are stroke patients' reports of their numbers of general practice consultations over 12 months?

BACKGROUND: Data on primary health care use are frequently used in economic evaluations. However, it is unclear how patient self-reports of their number of consultations with their general practitioner (GP) relate to actual consultations in the electronic records. These data are crucial if self-reports are used to conduct economic evaluations. OBJECTIVES: To report the accuracy of stroke patients' self-reports of their number of primary care consultations over a 12-month period by comparison with practice-held electronic records. We also recorded the number of contacts required to collect service use data from the practices. METHODS: We contacted 65 practices requesting electronic consultation records over 12 months for 115 stroke patients who took part in a trial of home blood pressure monitoring. Consultation rates from the electronic records were compared with patients' self-reported number of consultations from a questionnaire covering the same period. RESULTS: Fifty-one practices (78%) responded. Patients' questionnaires (n = 83) reported a mean of 5.7 consultations with their GP per year compared with 7.2 in the electronic records (difference 1.6, 95% confidence interval 0.5-2.7, P < 0.01). The mean time taken to obtain records from practices was 6 weeks. CONCLUSIONS: Patients modestly under-reported the number of consultations they had with a GP. Obtaining patient records from practices required more effort than obtaining information from patient questionnaires at the same time as assessing main trial outcomes. If patient self-reports of health care usage are used in economic evaluations in primary care, researchers should consider validating a sample against electronic records.

Where do sexually active female London students go to access healthcare? Evidence from the POPI (Prevention of Pelvic Infection) chlamydia screening trial.

BACKGROUND: Little is known about where sexually active female students access healthcare. OBJECTIVES: Using data from the Prevention of Pelvic Infection (POPI) cohort, the authors aimed to: Describe where sexually active female students aged ≤ 27 years reported accessing healthcare. Investigate the association between numbers of sexual partners during 12 months of follow-up and healthcare usage, health-related quality of life (EQ-5D) and demographic and behavioural characteristics. METHODS: Participants provided vaginal swabs and completed questionnaires on sexual health and quality of life at baseline and at a 12-month follow-up. The follow-up questionnaire also asked about healthcare attendances during the previous 12 months. Mann-Whitney tests were used to relate healthcare seeking behaviour and other characteristics to reported numbers of partners during follow-up. RESULTS: Of 1865 women included in the analysis, 79% paid at least one visit to their general practice during follow-up, 23% attended an accident and emergency/walk-in clinic, 21% a family planning clinic and 14% a genitourinary medicine clinic. As the number of sexual partners increased (0-1, 2-3, 4+), women were more likely to have visited a genitourinary medicine clinic (10%, 16%, 30%, p<0.001) or accident and emergency/walk-in clinic (21%, 26%, 29%, p<0.002). Women with more sexual partners were also more likely to smoke, use condoms, be aged <16 years at sexual debut, have bacterial vaginosis, chlamydia or gonorrhoea at baseline and to have lower EQ5-D scores. CONCLUSION: This is the first UK study of healthcare attendance in multiethnic female students recruited outside healthcare settings. The high attendance in general practice may represent a valuable opportunity for screening for sexually transmitted infections.

Assessment of GFR by four methods in adults in Ashanti, Ghana: the need for an eGFR equation for lean African populations.

BACKGROUND: Equations for estimating glomerular filtration rate (GFR) have not been validated in Sub-Saharan African populations, and data on GFR are few. METHODS: GFR by creatinine clearance (Ccr) using 24-hour urine collections and estimated GFR (eGFR) using the four-variable Modification of Diet in Renal Disease (MDRD-4)[creatinine calibrated to isotope dilution mass spectrometry (IDMS) standard], Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and Cockcroft-Gault equations were obtained in Ghanaians aged 40-75. The population comprised 1013 inhabitants in 12 villages; 944 provided a serum creatinine and two 24-hour urines. The mean weight was 54.4 kg; mean body mass index was 21.1 kg/m(2). RESULTS: Mean GFR by Ccr was 84.1 ml/min/1.73 m(2); 86.8% of participants had a GFR of >/=60 ml/min/1.73 m(2). Mean MDRD-4 eGFR was 102.3 ml/min/1.73 m(2) (difference vs. Ccr, 18.2: 95% CI: 16.8-19.5); when the factor for black race was omitted, the value (mean 84.6 ml/min/1.73 m(2)) was close to Ccr. Mean CKD-EPI eGFR was 103.1 ml/min/1.73 m(2), and 89.4 ml/min/1.73 m(2) when the factor for race was omitted. The Cockcroft-Gault equation underestimated GFR compared with Ccr by 9.4 ml/min/1.73 m(2) (CI: 8.3-10.6); particularly in older age groups. GFR by Ccr, and eGFR by MDRD-4, CKD-EPI and Cockcroft-Gault showed falls with age: MDRD-4 5.5, Ccr 7.7, CKD-EPI 8.8 and Cockcroft-Gault 11.0 ml/min/1.73 m(2)/10 years. The percentage of individuals identified with CKD stages 3-5 depended on the method used: MDRD-4 1.6% (7.2 % without factor for black race; CKD-EPI 1.7% (4.7% without factor for black race), Ccr 13.2% and Cockcroft-Gault 21.0%. CONCLUSIONS: Mean eGFR by both MDRD-4 and CKD-EPI was considerably higher than GFR by Ccr and Cockcroft-Gault, a difference that may be attributable to leanness. MDRD-4 appeared to underestimate the fall in GFR with age compared with the three other measurements; the fall with CKD-EPI without the adjustment for race was the closest to that of Ccr. An equation tailored specifically to the needs of the lean populations of Africa is urgently needed. For the present, the CKD-EPI equation without the adjustment for black race appears to be the most useful.

Blood Pressure and Haematological Indices in Twelve Communities in Ashanti, Ghana.

Hypertension is the most important risk factor for cardiovascular mortality and morbidity in Sub-Saharan Africa. In western populations, high haemoglobin levels are associated with raised BP unlike in Sub-Saharan Africa where there is a paucity of data. Our study examines the association between haematological indices with BP variables. Weight, height, BP, and whole blood indices of viscosity (Hb, haematocrit, RBC count, and MCV) were measured in 921 adults (340 men, 581 women; aged 40-75) in 12 communities in Ghana. Mean values for Hb (12.3 g/dl ± 1.7 SD), haematocrit (36.7% ± 5.2), RBC (4.10 million/µL ± 0.64), and MCV were lower than reference values used in Sub-Saharan Africa. Mean BMI was 21.1 ± 4.1 indicating a lean population. Systolic BP increased by 1.0 mmHg (95% CI 0.5-1.5), p < 0.001, for women and 0.5 (0.1-1.0), p = 0.027, for men per unit increase in haematocrit. Similar relationships were found for Hb and RBC but not for MCV or platelets. The relationships were weaker when adjusted for BMI, 0.7 mmHg (0.2-1.2) in women and 0.5 (0.0-1.0) in men. Findings for diastolic BP were similar. Overall haematological indices were low. We have found a significant, positive relationship between BP, Hb, Haematocrit, and RBC count in our population.

A community programme to reduce salt intake and blood pressure in Ghana [ISRCTN88789643].

BACKGROUND: In Africa hypertension is common and stroke is increasing. Detection, treatment and control of high blood pressure (BP) is limited. BP can be lowered by reducing salt intake. In Africa salt is added to the food by the consumer, as processed food is rare. A population-wide approach with programmes based on health education and promotion is thus possible. METHODS: We carried out a community-based cluster randomised trial of health promotion in 1,013 participants from 12 villages (628 women, 481 rural dwellers); mean age 55 years to reduce salt intake and BP. Average BP was 125/74 mmHg and urinary sodium (UNa) 101 mmol/day. A health promotion intervention was provided over 6 months to all villages. Assessments were made at 3 and 6 months. Primary end-points were urinary sodium excretion and BP levels. RESULTS: There was a significant positive relationship between salt intake and both systolic (2.17 mmHg [95% CI 0.44 to 3.91] per 50 mmol of UNa per day, p < 0.001) and diastolic BP (1.10 mmHg [0.08 to 1.94], p < 0.001) at baseline. At six months the intervention group showed a reduction in systolic (2.54 mmHg [-1.45 to 6.54]) and diastolic (3.95 mmHg [0.78 to 7.11], p = 0.015) BP when compared to control. There was no significant change in UNa. Smaller villages showed greater reductions in UNa than larger villages (p = 0.042). Irrespective of randomisation, there was a consistent and significant relationship between change in UNa and change in systolic BP, when adjusted for confounders. A difference in 24-hour UNa of 50 mmol was associated with a lower systolic BP of 2.12 mmHg (1.03 to 3.21) at 3 months and 1.34 mmHg (0.08 to 2.60) at 6 months (both p < 0.001). CONCLUSION: In West Africa the lower the salt intake, the lower the BP. It would appear that a reduction in the average salt intake in the whole community may lead to a small but significant reduction in population systolic BP.

Race-specific differences in antioxidant enzyme activity in patients with type 2 diabetes: a potential association with the risk of developing nephropathy.

OBJECTIVE: Lipid hydroperoxide, a marker of oxidative stress, is linked to the development of nephropathy and is reportedly higher in patients of African origin compared with Caucasians. This may be relevant to race-specific differences in susceptibility to nephropathy. We investigated whether alterations in antioxidant enzyme activity could account for this biochemical phenotype and examined the relationship with conventional markers of renal disease. RESEARCH DESIGN AND METHODS: Two hundred seventeen individuals were studied. Patients with type 2 diabetes (n = 75) of African and Caucasian origin were matched by sex and racial origin with healthy control subjects (n = 142). Plasma total superoxide dismutase (SOD) and glutathione peroxidase (GPx) activity were spectrophotometrically measured, and total cholesterol and triglycerides were measured by enzymatic methods. RESULTS: SOD activity was higher and GPx activity lower in patients with diabetes than in healthy control subjects (573 +/- 515 vs. 267 +/- 70 units/l, P < 0.001 and 150 +/- 93 vs. 178 +/- 90 units/l, P = 0.019, respectively). Patients of African origin with diabetes had lower GPx and higher SOD activity compared with Caucasian patients (126 +/- 82 vs. 172 +/- 97 units/l, P = 0.03 and 722 +/- 590 vs. 445 +/- 408 units/l, P = 0.002, respectively). Patients of African origin with normal urinary albumin excretion had significantly higher plasma creatinine concentrations (100.7 +/- 14.2 vs. 88.1 +/- 14.9 micromol/l, P = 0.007) and lower GPx activity (99.0 +/- 72.4 vs. 173.7 +/- 107.4 units/l, P = 0.02) compared with those of Caucasian origin. African origin was an independent predictor of elevated SOD (P = 0.007) and reduced GPx activity (P = 0.02) in regression analysis. CONCLUSIONS: SOD and GPx enzyme activities vary according to race and could account for differences in lipid hydroperoxide. In patients of African origin, susceptibility to renal disease may be associated with lowered GPx activity.

How big should the pilot study for my cluster randomised trial be?

There is currently a lot of interest in pilot studies conducted in preparation for randomised controlled trials. This paper focuses on sample size requirements for external pilot studies for cluster randomised trials. We consider how large an external pilot study needs to be to assess key parameters for input to the main trial sample size calculation when the primary outcome is continuous, and to estimate rates, for example recruitment rates, with reasonable precision. We used simulation to provide the distribution of the expected number of clusters for the main trial under different assumptions about the natural cluster size, intra-cluster correlation, eventual cluster size in the main trial, and various decisions made at the piloting stage. We chose intra-cluster correlation values and pilot study size to reflect those commonly reported in the literature. Our results show that estimates of sample size required for the main trial are likely to be biased downwards and very imprecise unless the pilot study includes large numbers of clusters and individual participants. We conclude that pilot studies will usually be too small to estimate parameters required for estimating a sample size for a main cluster randomised trial (e.g. the intra-cluster correlation coefficient) with sufficient precision and too small to provide reliable estimates of rates for process measures such as recruitment or follow-up rates.

What factors support older people to increase their physical activity levels? An exploratory analysis of the experiences of PACE-Lift trial participants.

BACKGROUND: Physical Activity (PA) has significant health benefits for older adults, but nearly all UK over 60's are not achieving recommended levels. The PACE-Lift primary care-based walking intervention for 60-75 year-olds used a structured, theoretically grounded intervention with pedometers, accelerometers, handbooks and support from practice nurses trained in behaviour change techniques. It demonstrated an objective increase in walking at 3 and 12 months. We investigated the experiences of intervention participants who did (and did not) increase their walking, in order to explore facilitators to increased walking. METHODS: Semi-structured telephone interviews used an interview schedule with a purposive sample of 30 intervention participants, 19 who had objectively increased their walking over the previous year and 11 who had not. Interviews were audio-recorded, transcribed and coded independently by researchers to generate a thematic coding framework. RESULTS: Both groups confirmed that walking was an appropriate PA for people of 'their age'. The majority of those with increased walking participated in the trial as a couple, were positive about individualised goal-setting, developed strategies for maintaining their walking, and had someone to walk with. Non-improvers reported their attempts to increase walking were difficult because of lack of social support and were less positive about the intervention's behaviour change components. DISCUSSION: Walking is an acceptable and appropriate PA intervention for older people. The intervention's goal-setting components were important for those who increased their walking. Mutual support between partners participating as a couple and having someone to walk with also facilitated increased walking.

Blood pressure and body mass index in lean rural and semi-urban subjects in West Africa.

BACKGROUND: Blood pressure (BP) is positively related to body mass index (BMI) in persons of both Caucasian and African origin, but the precise nature of the relationship is unclear. OBJECTIVE: To study the relationship between BP and BMI in a lean African population. DESIGN: A community-based cross-sectional study. METHODS: The BMI and BP were measured in 362 men and 592 women aged 40-75 years living in Ashanti, Ghana. In total, 498 lived in semi-urban areas and 456 in rural villages. RESULTS: The BMI was higher among semi-urban women [23.1 kg/m (95% confidence interval (CI), 22.5 to 23.6)] than semi-urban men [20.9 kg/m (95% CI, 20.6 to 21.5)], rural men [19.5 kg/m (95% CI, 19.1 to 19.9)] and rural women [19.9 kg/m (95% CI, 19.5 to 20.3)]. For systolic BP in women older than 52 years and in semi-urban women, the relationship was non-linear. The slope of the line below the change point ("knot") was greater than that above it. There was no evidence of non-linearity in men. For diastolic BP only younger women had a significant "knot" point at 18 kg/m. Again, the slope of the line below the "knot" was greater than that above it. In men, however, there was also evidence of a "knot" in younger and rural men, with the slope of the line below the "knot" being less that that above it (unlike in women). CONCLUSIONS: The relationship between BP and BMI is not linear, and is possibly sigmoid, but this may vary between subgroups.

Rural and semi-urban differences in salt intake, and its dietary sources, in Ashanti, West Africa.

OBJECTIVES: To provide a socioeconomic profile of rural and semi-urban settings in Ashanti, West Africa and to investigate the relationship between urbanization and sources of salt in the diet. SETTING: 12 villages (6 rural, 6 semi-urban) participating in a cluster randomized controlled trial of a health promotion in the Ashanti region of Ghana. PARTICIPANTS: 1013 adult men (N = 385) and women (N = 628), aged 40-75. METHOD: Between June 2001 and June 2002, participants completed a detailed questionnaire on demography, occupation and education, housing, radio and television use, personal and family medical history, drug therapy, smoking, alcohol consumption, and diet. RESULTS: 532 subjects lived in semi-urban and 481 in rural communities. Ninety-two percent of the participants were of the Ashanti tribe and 94% spoke Twi. The semi-urban villages were closer to Kumasi, the second largest city in Ghana, had larger population (1727 vs 1100 people) and household sizes (14.6 vs 8.8 persons per household; P < .001), had fewer farmers (53% vs 81%; P < .001) and more traders (22% vs 7%; P < .001), and had more homes with electricity (81% vs 17%; P < .001) and piped water (28% vs 0.2%; P < .05). Semi-urban villagers had higher systolic blood pressure than rural villagers (129 vs 121 mm Hg difference 8 mm Hg [95% CI 5-11]; P < .001). Salt is almost invariably added to food in cooking (98%), and salted foods such as fish and meat are eaten in both communities. Salt is often added at the table (52%), more often in rural villages than in semi-urban settings (59% vs 45%; P < .01), although the total salt consumed as measured by urinary sodium was similar (99 vs 103 mmol/day). Potassium levels were higher in rural villages (58 vs 40 mmol/day difference 18 mmol/day [95% CI 11-26]; P < .001). CONCLUSIONS: In this mainly farming community were clear differences in housing, population structure, and blood pressure between rural and semi-urban communities. While no significant differences were in the amount of salt consumed, the sources of salt differed between rural and semi-urban settings. Finally, rural villagers ate more potassium than semi-urban participants.