Determination of the minimal clinically important difference for seven measures of fatigue in Swedish patients with systemic lupus erythematosus.

OBJECTIVE: To estimate the minimal clinically important difference (MCID) in seven self-administered measures assessing fatigue in Swedish patients with systemic lupus erythematosus (SLE). METHOD: The participants (n = 51, women 98%, age 52.8 ± 12.1 years, disease duration 18.7 ± 13.6 years) met in groups of six to nine persons. After completing seven fatigue questionnaires [the Fatigue Severity Scale (FSS); the Multidimensional Assessment of Fatigue (MAF) scale; the 20-item Multidimensional Fatigue Inventory (MFI); the Chalder Fatigue Scale (CFS); the Short Form-36 Vitality subscale (VT); the Functional Assessment of Chronic Illness Therapy - Fatigue (FACIT-F) scale; and the Numeric Rating Scale (NRS)], each respondent had a minimum of five face-to-face discussions, followed by an individual comparative assessment of their own level of fatigue (seven-grade scale). This method resulted in 260 contrasting assessments; MCIDs were first calculated using the paired differences and then established by a regression approach. Patients were asked to comment on their experience with the questionnaires and whether they captured their fatigue adequately. RESULTS: The paired approach (using 'little more fatigue' as an anchor for MCID during the face-to-face comparative assessments) provided estimates of 4.6-17.0; the regression approach provided estimates of 4.3-10.8. Estimates using the regression approach were consistently lower than those using the paired model. The MCID estimates were least favourable and fewer respondents supported the use of the NRS compared to the other self-reported questionnaires. CONCLUSIONS: All seven instruments detect MCIDs for fatigue in Swedish patients with SLE. However, the single-question measure was not supported by the MCID estimates or by comments from the respondents.

Influence of lifetime hip joint force on the risk of self-reported hip osteoarthritis: a community-based cohort study.

OBJECTIVE: To investigate the influence of cumulative lifetime hip joint force on the risk of self-reported medically-diagnosed hip osteoarthritis (OA). DESIGN: Prospective cohort. SETTING: General population. PARTICIPANTS: Members of Canadian Association of Retired Persons, community-dwelling. MAIN OUTCOME: Health-professional diagnosed hip OA, self-reported. METHODS: Exposure data on lifetime physical activity type (occupational, household, sport) and dose (frequency, intensity, duration) was collected in 2005. Subjects were ranked in terms of a 'cumulative peak force index' (CFPI), a measure of lifetime mechanical hip joint force. Multivariable survival analyses were performed to obtain adjusted effects for mean lifetime exposure and during 5-year age periods. RESULTS: Of 2918 subjects aged 45-85, 176 (6.03%) developed hip OA during the 2-year follow up (43 men, 133 women). The highest quintile of mean lifetime hip CPFI (HR 2.32; 95% CI 1.31-4.12), and high hip force in three age periods (35-39, 40-44, 45-49) were independently associated with hip OA. Previous hip injury was an approximate five-fold risk for development of hip OA across all models. In analysis by activity domain (occupation, sport, household), there was a trend (non-significant) for the highest quintile of occupational force, but not sport or household, to be associated with hip OA. CONCLUSIONS: A newly proposed measure of lifetime mechanical hip force was used to estimate the risk of self-reported, medically-diagnosed hip OA. While there are important limitations, this prospective study suggests that lifelong physical activity is generally safe. Very high levels of lifetime force from all domains combined, and in particular from occupational forces, may be important in the etiology of hip OA.

The mood stabilizers lithium and valproate selectively activate the promoter IV of brain-derived neurotrophic factor in neurons.

Brain-derived neurotrophic factor (BDNF) has been strongly implicated in the synaptic plasticity, neuronal survival and pathophysiology of depression. Lithium and valproic acid (VPA) are two primary mood-stabilizing drugs used to treat bipolar disorder. Treatment of cultured rat cortical neurons with therapeutic concentrations of LiCl or VPA selectively increased the levels of exon IV (formerly rat exon III)-containing BDNF mRNA, and the activity of BDNF promoter IV. Surprisingly, lithium- or VPA-responsive element(s) in promoter IV resides in a region upstream from the calcium-responsive elements (CaREs) responsible for depolarization-induced BDNF induction. Moreover, activation of BDNF promoter IV by lithium or VPA occurred in cortical neurons depolarized with KCl, and deletion of these three CaREs did not abolish lithium- or VPA-induced activation. Lithium and VPA are direct inhibitors of glycogen synthase kinase-3 (GSK-3) and histone deacetylase (HDAC), respectively. We showed that lithium-induced activation of promoter IV was mimicked by pharmacological inhibition of GSK-3 or short interfering RNA (siRNA)-mediated gene silencing of GSK-3alpha or GSK-3beta isoforms. Furthermore, treatment with other HDAC inhibitors, sodium butyrate and trichostatin A, or transfection with an HDAC1-specific siRNA also activated BDNF promoter IV. Our study demonstrates for the first time that GSK-3 and HDAC are respective initial targets for lithium and VPA to activate BDNF promoter IV, and that this BDNF induction involves a novel responsive region in promoter IV of the BDNF gene. Our results have strong implications for the therapeutic actions of these two mood stabilizers.

Specific defects, surface band bending and characteristic green emissions of ZnO.

The green emission in ZnO can be identified as two characteristic emissions, namely high and low energy emissions, respectively. The study of band bending effect of ZnO surface demonstrates that oxygen vacancies cause both the core level and the valence band to shift to higher binding energy. The downward band bending induced by a strong accumulation layer, where the oxygen vacancies act as donors, results in the high energy green emission. ZnO with the low energy green emission has Zn 2p 3/2 core level binding energy shifted to lower binding energy. The depth of dominant oxygen vacancies plays an important role in determining the mechanisms of green emission.

Correlation between the characteristic green emissions and specific defects of ZnO.

In this work, the correlation between the characteristic green emissions and specific defects of ZnO was investigated through a series of experiments that were designed to separate the subtle interplays among the various types of specific defects. With physical analysis and multimode Brownian oscillator modeling, the underlying mechanisms of the variant effects on green emission were revealed. The results demonstrate that the observed green emissions can be identified as two types of individual emissions, namely high energy and low energy, that are associated with specific defects and their locations. The surface modification that leads to downwards band bending was found to be responsible for the high-energy green emission. The relationship between the intensity of the low- energy green emission and the crystallographic lattice contraction indicates that oxygen vacancy is the dominant cause of such an emission that resides within the bulk of ZnO.

Is misoprostol cost-effective in the prevention of nonsteroidal anti-inflammatory drug-induced gastropathy in patients with chronic arthritis? A review of conflicting economic evaluations.

Whether misoprostol, a synthetic prostaglandin E1 analogue, should be routinely prescribed along with nonsteroidal anti-inflammatory drugs (NSAIDS) to prevent gastric damage is of great clinical importance and has profound cost implications. No consensus exists on whether misoprostol cotherapy results in a cost-saving, is cost-effective, or is costly. The different conclusions reached by five economic evaluations of misoprostol can be explained solely by the assumed absolute risk reduction of symptomatic ulcer, which was more than seven times greater in the studies that concluded that misoprostol was cost-effective than in a study that concluded misoprostol to be costly. Since no study has directly shown the effectiveness of misoprostol cotherapy in preventing clinically significant ulcer disease (ie, hemorrhage and perforation), it is impossible to judge which assumptions are most appropriate. The absence of firm data on the rate of NSAID-induced gastric ulcers reduced by misoprostol makes it impossible to conclude whether it is cost-effective in patients with chronic arthritis who use NSAIDS.

Marginal benefit of renal biopsy in systemic lupus erythematosus.

The predictive information provided by renal biopsy was assessed for four systemic lupus erythematosus (SLE) patient populations and compared with the predictive information from clinical data without benefit of biopsy, both measured against actual outcome. Renal biopsy results, whether studied by light or electron microscopy, contain important prognostic information. However, the prognostic information from renal biopsies in these patient groups is generally less than that of even the simplest clinical classifications; and when combined with clinical information, the total prognostic content is essentially that of the clinical information alone. Thus, judged by presently available data, the renal biopsy in SLE provides mainly redundant prognostic information. The marginal benefit is the difference between what is known before and after a test. Quantitation of predictive accuracy allows assessment of marginal benefit, that is, the increment in accuracy afforded by an additional test. Costly and potentially hazardous procedures, such as renal biopsy, require reassessment in terms of marginal rather than absolute predictive ability.

Teaching of primary care in an internal medicine residency program.

A teaching module in ambulatory internal medicine has been added to a residency program in a large referral hospital. The effort was directed to structure a program of instruction reflecting common problems seen by primary care internists. Patients were screened by supervising staff to make the rotation an efficient learning experience. Experienced nurse clinicians were used to monitor patients with stabilized medical problems, thus freeing the housestaff for problems more suited to their level of training. The nurses also served as role models with which the housestaff could interact and provide continuity and accessibility of care to patients being followed up by transient physicians-in-training. Various teaching conferences based on traditional inpatient models were conducted. Self-assessment and peer review techniques were structured around monthly conferences in which medical records were assessed by each participant.

The cost-effectiveness of vaccination against Lyme disease.

BACKGROUND: Vaccination against Lyme disease appears to be safe and effective; however, the cost per quality-adjusted life-year (QALY) gained with vaccination is unknown. METHODS: We developed a decision-analytic model to evaluate the cost-effectiveness of vaccination compared with no vaccination in individuals living in endemic areas of Lyme disease. Our analysis encompassed a 10-year time horizon including a 2-year vaccination schedule with an additional year of vaccine effectiveness. The costs and probabilities of vaccination risk, compliance and efficacy, and Lyme disease clinical sequelae and treatment were estimated from the literature. Health-related quality-of-life weights of the various clinical sequelae of Lyme disease infection were obtained from a sample of 105 residents from Nantucket Island, Massachusetts. RESULTS: Vaccinating 10 000 residents living in endemic areas with a probability of Lyme disease per season of 0.01 averted 202 cases of Lyme disease during a 10-year period. The additional cost per QALY gained compared with no vaccination was $62 300. Vaccination cost $12 600/QALY gained for endemic areas with an attack rate of 2.5% per season, and $145 200/QALY gained for an attack rate of 0.5%. Vaccinating individuals over an accelerated 2-month vaccination schedule improved the cost-effectiveness to $53 700/QALY gained. If a yearly booster shot is required for persisting efficacy, the marginal cost-effectiveness ratio increases to $72 700/QALY. The cost-effectiveness of vaccination was most sensitive to the Lyme disease treatment efficacy and assumptions about the persistence of vaccination effect. CONCLUSION: Vaccination against Lyme disease appears only to be economically attractive for individuals who have a seasonal probability of Borrelia burgdorferi infection of greater than 1%.

Monoclonal gammopathy of undetermined significance and exposure to breast implants.

BACKGROUND: Animal studies and uncontrolled case series in humans have suggested a possible association between breast implant exposure and monoclonal gammopathy. OBJECTIVE: To assess whether there is an increased risk of monoclonal gammopathy in women with silicone breast implants, we conducted a retrospective study of women exposed to breast implants and matched nonexposed women nested within a prospective cohort study (the Nurses' Health Study). METHODS: We used serum protein electrophoresis and immunoglobulin subtype by immunofixation to test 288 women exposed to breast implants and 288 age-matched, nonexposed women who previously had provided a blood sample (1989-1990) for monoclonal proteins. RESULTS: Among the women exposed to breast implants, 5 had monoclonal gammopathy of undetermined significance (MGUS) compared with 4 women among those not exposed (odds ratio, 1.25; 95% confidence interval, 0.27-6.39). The distribution of isotypes was similar across exposure groups. The exposed women with MGUS tended to be older than the nonexposed women (mean age, 60.4 years vs 52.5 years, respectively; P =.03). None of the 9 women with MGUS had reported multiple myeloma or other hematologic malignancies up through 1996. CONCLUSIONS: We find little evidence to support a substantial increased risk of MGUS in women exposed to breast implants. Larger studies are needed to determine if a more modest relationship exists.

Physician extenders in walk-in clinics: a prospective evaluation of the AMOSIST program.

The Automated Military Outpatient System (AMOS) Project was developed to improve the ambulatory care of patients with episodic and chronic illnesses. During the development of its episodic care component, the relative frequency of problems treated by the walk-in clinic staff was analyzed and showed a high volume of acute minor illnesses. A simple, conservative triage system run by non-professionals was developed to screen patients to a clinic for benign, self-limited illnesses run by physician-extenders. This group, the equivalent of civilian licensed practical nurses and nurses' aides, was trained in a task-oriented fashion to treat 44 common minor illnesses. Clinical algorithms for these illnesses were developed and used as training tools, memory aids, and auditing instruments. This program is now operating in 26 US Army hospitals and caring for some 44,000 patients a month in the continetal United States. We report the results of a prospective audit of the corpsmen and a study of the patient attitude and acceptance of the program.

Gender differences in patient preferences may underlie differential utilization of elective surgery.

PURPOSE: To study gender-specific preferences regarding timing of elective total joint replacement (TJR) surgery in patients with moderately severe osteoarthritis (OA) of the hip or knee. PATIENTS AND METHODS: Focus group discussions regarding TJR surgery were conducted among 18 women and among 12 men with moderately severe OA of the hip or knee. Discussions were tape recorded, transcribed, coded for themes, and evaluated semiquantitatively and qualitatively for gender differences. RESULTS: In general, men were more likely to choose surgery earlier in the disease than women and had higher expectations for surgical success. Women were more fearful of surgery. Women preferred to suffer arthritis pain rather than risk surgery, and indicated they would delay surgery to await better technology and to avoid disrupting caregiving roles for dependent spouses and others. CONCLUSION: Men and women differ in their willingness to accept continued functional decline, risks of surgery, and disruption of usual role. Gender differences may influence decisions regarding utilization of TJR.

Utilization of rheumatology physician services by the elderly.

PURPOSE: To examine rheumatology subspecialty practice patterns, determinants of referral to rheumatologists, and utilization of aspiration and injection procedures in a population-based sample of elderly individuals. SUBJECTS AND METHODS: We obtained Medicare physician claims for all visits to rheumatologists among beneficiaries aged 65 years and older in Colorado, Massachusetts, and Virginia in 1993, and for visits to all providers by patients with coded diagnoses of rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). We examined variations in visit frequency and aspiration/injection procedures, and we analyzed determinants of referral to a rheumatologist for RA or SLE. RESULTS: In 1 year, 144,797 visits were made to rheumatologists by 38,443 patients in the three states. An inflammatory disorder was coded in 45% of visits and a noninflammatory disorder in 50%. Half of patients with RA were seen three or fewer times in the year. For RA and SLE, African Americans were about 60% as likely to be seen by a rheumatologist as whites. Utilization of rheumatologist services for rheumatoid arthritis and systemic lupus erythematosus was highest in the state (Virginia) with the lowest per capita supply of rheumatologists. Among patients with bursitis, tendinitis, and osteoarthritis, African-American women were more likely to receive an injection or aspiration procedure than whites or African-American men. CONCLUSION: Elderly patients with rheumatologic disorders were seen by specialists less frequently than recommended by a recent rheumatology manpower survey. African-Americans with RA and SLE had fewer rheumatology visits than whites.

Association of silicone breast implants with immunologic abnormalities: a prospective study.

PURPOSE: To study the possible association of silicone-breast-implant exposure and immunologic abnormalities within the Nurses' Health Study, an ongoing prospective cohort study of women. SUBJECTS AND METHODS: From this cohort, we randomly selected 200 women who had been exposed to silicone breast implants and who had never reported connective tissue diseases during 14 years of follow-up, and 500 age-matched, nonexposed women, including 100 with definite connective tissue diseases validated by medical record review, 100 with at least one symptom of a connective tissue disease, 100 with diabetes, and 200 healthy controls. Assays for antinuclear antibodies (ANA), including anti-dsDNA, anti-ssDNA, anti-Sm/RNP/Ro/La, and anti-Scl-70, rheumatoid factor, immunoglobulins, serum complement, and C-reactive protein level, and anticardiolipin, antithyroglobulin, antithyroid microsomal, and antisilicone antibodies were performed by standard techniques in blood samples collected in 1989 or 1990 before collection of silicone-breast-implant exposure data in 1992. RESULTS: ANA was positive (> or = 1:40) in 14% of women with silicone breast implants compared with 20% of healthy women (P = 0.11). Rheumatoid factor was positive (> or = 1:40) in 5% of women with silicone breast implants and 2% of healthy women (P = 0.16). Women with silicone breast implants had a significantly higher frequency of anti-ssDNA antibodies than healthy women (41% and 29%, P = 0.012). Duration of implant was associated with a higher frequency of anti-ssDNA antibodies (P = 0.03) but not with ANA or rheumatoid factor. No other significant differences in the frequencies of autoantibodies were observed in silicone breast implant-exposed women. Antisilicone antibodies were not found in any sample. CONCLUSION: We found no increased frequency of any immunologic abnormalities in women exposed to silicone breast implants, except for anti-ssDNA, which has unknown clinical relevance.

A connective tissue disease screening questionnaire for population studies.

To develop a technique to screen populations for potential connective tissue disease (CTD), we mailed a 30-item questionnaire to 253 randomly selected patients with systemic lupus erythematosus, rheumatoid arthritis, scleroderma, polymyositis, dermatomyositis, mixed connective tissue disease (MCTD), or Sjögren's syndrome and to 340 randomly selected control subjects. The response rate after four mailings was 71% for case subjects and 54% for control subjects. Test-retest reliability for detection of any CTD was 0.82. Sensitivity for specific CTDs was 83 to 96% and specificity was 83 to 93%. The positive predictive value for any CTD (assuming an overall prevalence of 1.3%) was 5.5%; negative predictive value was 99.7%. The CTD Screening Questionnaire has high sensitivity and specificity for screening large populations.

Yield of mtDNA mutation analysis in 2,000 patients.

The multiplex polymerase chain reaction-allele specific oligonucleotides (PCR/ASO) dot blot hybridization method was used to detect 44 mitochondrial DNA point mutations in 2,000 patients suspected as having mitochondrial DNA disorders. These point mutations are classified into four categories. Category I consists of primary disease-causing, heteroplasmic point mutations. Homoplasmic nucleotide substitutions that have been reported to be possibly disease associated are in Category II. Homoplasmic nucleotide substitutions that are thought to be benign polymorphism are included in category III. The novel nucleotide substitutions recently discovered in our laboratory by single strand conformation polymorphism analysis are in category IV. Frequencies of these 44 nucleotide substitutions in 2,000 patients and 262 control individuals were studied. The results indicated that analysis of 12 recurrent disease-causing point mutations in category I identified 5.4% of the patients suspected as having mitochondrial DNA disorders. Since the mitochondrial disorders are a group of complex, heterogeneous, and multisystemic diseases, it is often difficult to confirm clinical diagnosis without molecular studies. Thus, the multiplex PCR/ASO method is an effective approach for initial screening of mtDNA mutations in patients suspected as having mitochondrial DNA disorders.

Relative responsiveness of condition-specific and generic health status measures in degenerative lumbar spinal stenosis.

The objective of this study was to compare the relative responsiveness of a condition-specific spinal stenosis measure and two generic health status measures for outcome assessment of surgery for degenerative lumbar spinal stenosis, and to examine whether responsiveness statistics and measures of the ability to distinguish clinically important improvement rank the instruments consistently. Physical function and symptom severity scales of the spinal stenosis measure were compared to the Sickness Impact Profile (SIP) and the Roland scale, which is derived from the SIP. Responsiveness was calculated with the standardized response mean, the effect size, and Guyatt's responsiveness statistic. The discriminative ability of the instruments to distinguish patients who improved from those who did not was assessed using satisfaction with surgery as an external criterion. Minimal clinically relevant improvement was estimated using patient satisfaction as the external criterion. All responsiveness statistics revealed the same order of responsiveness; the physical function scale (SRM = 1.07) and symptom severity scales (SRM = 0.96) were more responsive than the Roland scale (SRM = 0.77) which was only slightly more responsive than the SIP (SRM = 0.69). Strikingly, the physical dimension of the SIP (SRM = 0.62) was even less responsive than the global SIP. The shape of and the area under the ROC curves showed that the physical function and symptom severity scales discriminate better between satisfied and unsatisfied patients than the Roland scale and SIP. The sensitivity to detect clinically important changes was somewhat lower at the ends of the scales, especially for the SIP and the Roland scale. Statistical approaches that assess the ability to distinguish clinically important changes and overall responsiveness statistics ranked the measures consistently. On the basis of these findings, we suggest that a condition-specific spinal stenosis measure is preferable as the primary end point in evaluative studies of degenerative lumbar spinal stenosis.

Interpretation of change scores in ordinal clinical scales and health status measures: the whole may not equal the sum of the parts.

The objective of this study was to analyze the problem of interpreting change scores of ordinal health status measures for clinical research or practice. Methods used included exploration of the generation of change scores in the physical ability scale of the SF-36, one of the most widely used generic health status instruments. Resulting data are presented as the ranking of items according to baseline score; a percentage of patients with severe difficulty and Rasch analysis provided the same rank order of item difficulty. On the interval scale provided by the Rasch model a concentration of items reflecting moderate difficulty occurred. This "inflates" numerical gains for patients with moderate disability compared to patients with very severe or minor physical disability. Calibration of change scores using patient perception of the level of change in function showed important variation of numerical gains with baseline. We conclude that numerically equal gains may differ in their meaning depending on baseline health status. It is recommended that distribution of baseline health status measures and distribution of responders by baseline status be reported in evaluative studies.

Validation of a meta-analysis: the effects of fish oil in rheumatoid arthritis.

The purpose of this study was to validate the results of a meta-analysis showing the efficacy of fish oil in rheumatoid arthritis with the results of a re-analysis of the complete primary data set. A Medline search yielded seven published papers. Three additional trials were found by contacting authorities in the field. Inclusion criteria included (1) a double-blind, placebo-controlled study, (2) use of at least one of seven predetermined outcome measures, (3) results reported for both placebo and treatment groups at baseline and follow-up, (4) randomization, and (5) parallel or cross-over design. Papers were scored for quality. Demographic and outcomes variables were collected. For the re-analysis of the primary data, the same variables were abstracted for the 395 individual patients randomized. The meta-analysis demonstrated that dietary fish oil supplementation for 3 months significantly reduced tender joint count (rate difference [RD] [95% CI] = -2.9 [-3.8 to -2.1] [p = 0.001]) and morning stiffness (RD [95% CI] = -25.9 [-44.3 to -7.5] [p < 0.01]) as compared with heterogeneous dietary control oils. The re-analysis of the primary data confirmed a significant reduction in tender joint count (p = 0.001) and in morning stiffness (p < 0.02) in the parallel analysis that ignored interaction terms. The analyses that included an interaction term between site and treatment again confirmed a significant reduction in tender joint count. The results for morning stiffness were similar to the meta-analysis, but did not quite reach statistical significance (p = 0.052-0.083). The relative improvements in the other outcome variables did not reach statistical significance. Use of fish oil improved the number of tender joints and duration of morning stiffness at 3 months as analyzed by both meta- and mega-analysis. The fuller mega-analysis confirmed the results of the meta-analysis. The advantages of mega-analysis were as follows: (1) the ability to analyze the homogeneity of the patient populations, (2) the ability to make clinically sensible adjustments in the form of the comparison, and (3) the ability to examine subsets of the data.