Building on existing tools to improve chronic disease prevention and screening in public health: a cluster randomized trial.

BACKGROUND: The BETTER (Building on Existing Tools to Improve Chronic Disease Prevention and Screening in Primary Care) intervention was designed to integrate the approach to chronic disease prevention and screening in primary care and demonstrated effective in a previous randomized trial. METHODS: We tested the effectiveness of the BETTER HEALTH intervention, a public health adaptation of BETTER, at improving participation in chronic disease prevention and screening actions for residents of low-income neighbourhoods in a cluster randomized trial, with ten low-income neighbourhoods in Durham Region Ontario randomized to immediate intervention vs. wait-list. The unit of analysis was the individual, and eligible participants were adults age 40-64 years residing in the neighbourhoods. Public health nurses trained as "prevention practitioners" held one prevention-focused visit with each participant. They provided participants with a tailored prevention prescription and supported them to set health-related goals. The primary outcome was a composite index: the number of evidence-based actions achieved at six months as a proportion of those for which participants were eligible at baseline. RESULTS: Of 126 participants (60 in immediate arm; 66 in wait-list arm), 125 were included in analyses (1 participant withdrew consent). In both arms, participants were eligible for a mean of 8.6 actions at baseline. At follow-up, participants in the immediate intervention arm met 64.5% of actions for which they were eligible versus 42.1% in the wait-list arm (rate ratio 1.53 [95% confidence interval 1.22-1.84]). CONCLUSION: Public health nurses using the BETTER HEALTH intervention led to a higher proportion of identified evidence-based prevention and screening actions achieved at six months for people living with socioeconomic disadvantage. TRIAL REGISTRATION: NCT03052959 , registered February 10, 2017.

Perioperative outcomes of women with and without class III obesity undergoing hysterectomy for endometrioid endometrial cancer: A population-based study.

OBJECTIVE: Population-based data on perioperative complications among women with endometrial cancer and severe obesity are lacking. We evaluated 30-day complication rates among women with and without class III obesity (body mass index ≥ 40 kg/m2) undergoing primary surgical management for endometrioid endometrial cancer (EEC), and how outcomes differed according to surgical approach (open vs. minimally invasive). METHODS: We performed a retrospective population-based cohort study of women with EEC undergoing hysterectomy in Ontario, Canada, between 2006 and 2015. We evaluated perioperative complications in the whole cohort, and in a 1:1 matched analysis using hard and propensity score matching to ensure similar distributions of patient, tumour, provider and institution-level factors between women with and without class III obesity (identified using a surgical billing code). The primary outcome of interest was the 30-day perioperative complication rate. RESULTS: 12,112 women met inclusion criteria; 2697 (22.3%) had class III obesity. We matched 2320 (86%) women with class III obesity to those without. The composite complication rate was significantly higher among women with class III obesity (23.2% vs. 18.4%, standardized mean difference [SMD] = 0.12), primarily due to wound infection/disruption (12.1% vs. 6.2%). There was no difference in outcomes for women with and without class III obesity when a minimally invasive approach was used. CONCLUSIONS: Wound infection/disruption was increased for women with class III obesity compared to women without. Otherwise, perioperative complications were similar between the matched pairs. When minimally invasive approaches were used, women with class III obesity had a similar risk of complications as women without obesity.

Does the presence of an intact primary increase the risk of nonelective colorectal surgery in patients treated with bevacizumab?

AIM: In patients with incurable metastatic colorectal cancer (mCRC), resection of the primary tumour is debated; however, patients with intact primaries may be at a higher risk of complications requiring surgery when receiving treatment with bevacizumab. Our aim was to estimate the risk of nonelective colorectal surgery in patients undergoing bevacizumab therapy for mCRC and evaluate the association between intact primary tumours and risk of nonelective surgery. METHOD: We designed a population-based, retrospective cohort study using administrative and cancer registry data in Ontario, Canada. We included patients with mCRC who received bevacizumab from 1 January 2008 to 31 December 2014. The primary outcome was nonelective colorectal surgery after initiation of bevacizumab. We determined the cumulative incidence of nonelective colorectal surgery among patients with previously resected and unresected primaries, accounting for the competing risk of death. We explored the relationship between previous resection of the primary and need for nonelective surgery using a cause-specific hazards model, controlling for patient, tumour and treatment factors. RESULTS: We identified 1840 (32.7%) patients with intact primaries and 3784 (67.3%) patients with prior resection. The cumulative incidence of nonelective surgery 1 year after initiating bevacizumab for all patients was 3.9% (95% CI 3.4-4.5%). One-year cumulative incidence was higher in those with intact primaries than in those with resected primaries (6.1% vs 2.9%, P < 0.0001). After adjustment, an intact primary remained strongly associated with nonelective colorectal surgery (hazard ratio = 2.89, 95% CI 2.32-3.61; P < 0.0001). CONCLUSION: Bevacizumab is associated with a low but meaningful risk for serious gastrointestinal complications, necessitating vigilance, particularly among patients with an intact primary tumour.

Refined estimates of local recurrence risks by DCIS score adjusting for clinicopathological features: a combined analysis of ECOG-ACRIN E5194 and Ontario DCIS cohort studies.

PURPOSE: Better tools are needed to estimate local recurrence (LR) risk after breast-conserving surgery (BCS) for DCIS. The DCIS score (DS) was validated as a predictor of LR in E5194 and Ontario DCIS cohort (ODC) after BCS. We combined data from E5194 and ODC adjusting for clinicopathological factors to provide refined estimates of the 10-year risk of LR after treatment by BCS alone. METHODS: Data from E5194 and ODC were combined. Patients with positive margins or multifocality were excluded. Identical Cox regression models were fit for each study. Patient-specific meta-analysis was used to calculate precision-weighted estimates of 10-year LR risk by DS, age, tumor size and year of diagnosis. RESULTS: The combined cohort includes 773 patients. The DS and age at diagnosis, tumor size and year of diagnosis provided independent prognostic information on the 10-year LR risk (p ≤ 0.009). Hazard ratios from E5194 and ODC cohorts were similar for the DS (2.48, 1.95 per 50 units), tumor size ≤ 1 versus  > 1-2.5 cm (1.45, 1.47), age ≥ 50 versus < 50 year (0.61, 0.84) and year ≥ 2000 (0.67, 0.49). Utilization of DS combined with tumor size and age at diagnosis predicted more women with very low (≤ 8%) or higher (> 15%) 10-year LR risk after BCS alone compared to utilization of DS alone or clinicopathological factors alone. CONCLUSIONS: The combined analysis provides refined estimates of 10-year LR risk after BCS for DCIS. Adding information on tumor size and age at diagnosis to the DS adjusting for year of diagnosis provides improved LR risk estimates to guide treatment decision making.

Uptake of Cancer Screening Tests Among Recipients of Solid Organ Transplantation.

Population-based cancer screening recommendations are also suggested for solid organ transplant recipients (SOTR); however, recommendation adherence is unknown. In a population-based cohort of SOTR in Ontario between 1997 and 2010, we determined the uptake of breast, cervical, and colorectal cancer screening tests and identified factors associated with up-to-date screening using recurrent event analysis. We identified 4436 SOTR eligible for colorectal, 2252 for cervical, and 1551 for breast cancer screening. Of those, 3437 (77.5%), 1572 (69.8%), and 1417 (91.4%), respectively, were not up-to-date for cancer screening tests during the observation period. However, these rates are likely an overestimate due to the inability to differentiate between tests done for screening or for diagnosis. SOTR with fewer comorbidities had higher rates of becoming screen up-to-date. Assessment by a primary care provider (PCP) was associated with becoming up-to-date with cancer screening (breast relative risk [RR] = 1.40, 95% confidence interval [CI]: 1.12-1.76, cervical RR = 1.29, 95% CI: 1.06-1.57, colorectal RR = 1.30, 95% CI: 1.15-1.48). Similar results were observed for continuity of care by transplant specialist at a transplant center. In conclusion, cancer screening for most SOTR does not adhere to standard recommendations. Involvement of PCPs in posttransplant care and continuity of care at a transplant center may improve the uptake of screening.

A centrally generated primary care physician audit report does not improve colonoscopy uptake after a positive result on a fecal occult blood test in Ontario's ColonCancerCheck program.

BACKGROUND: Timely follow-up of fecal occult blood screening with colonoscopy is essential for achieving colorectal cancer mortality reduction. In the present study, we evaluated the effectiveness of centrally generated, physician-targeted audit and feedback to improve colonoscopy uptake after a positive fecal occult blood test (fobt) result within Ontario's population-wide ColonCancerCheck Program. METHODS: This prospective cohort study used data sets from Ontario's ColonCancerCheck Program (2008-2011) that were linked to provincial administrative health databases. Cox proportional hazards regression was used to estimate the effect of centralized, physician-targeted audit and feedback on colonoscopy uptake in an Ontario-wide fobt-positive cohort. RESULTS: A mailed physician audit and feedback report identifying individuals outstanding for colonoscopy for 3 or more months after a positive fobt result did not increase the likelihood of colonoscopy uptake (hazard ratio: 0.95; 95% confidence interval: 0.79 to 1.13). Duration of positive fobt status was strongly inversely associated with the hazard of follow-up colonoscopy (p for linear trend: <0.001). CONCLUSIONS: In a large population-wide setting, centralized tracking in the form of physician-targeted mailed audit and feedback reports does not improve colonoscopy uptake for screening participants with a positive fobt result outstanding for 3 or more months. Mailed physician-targeted screening audit and feedback reports alone are unlikely to improve compliance with follow-up colonoscopy in Ontario. Other interventions such as physician audits or automatic referrals, demonstrated to be effective in other jurisdictions, might be warranted.

Annual surveillance mammography after early-stage breast cancer and breast cancer mortality.

BACKGROUND: After treatment for early-stage breast cancer (bca), annual surveillance mammography (asm) is recommended based on the assumption that early detection of an invasive ipsilateral breast tumour recurrence or subsequent invasive contralateral primary bca reduces bca mortality. METHODS: We studied women with unilateral early-stage bca treated by breast-conserving surgery from 1994 to 1997 who subsequently developed an ipsilateral recurrence or contralateral primary more than 24 months after initial diagnosis, without prior regional or distant metastases. Annual surveillance mammography was defined as 2 episodes of bilateral mammography 11-18 months apart during the 2 years preceding the ipsilateral recurrence or contralateral primary. The association between asm and bca death was evaluated using a Cox proportional hazards model. RESULTS: We identified 669 women who experienced invasive ipsilateral recurrence (n = 455) or a contralateral primary (n = 214) at a median interval of 53 months [interquartile range (iqr): 37-72 months] after initial diagnosis, 64.7% of whom had received asm during the preceding 2 years. The median interval between the 2 bilateral mammograms was 12.3 months (iqr: 11.9-13.0 months), and the median interval between the 2nd mammogram and histopathologic confirmation of ipsilateral recurrence or contralateral primary was 1.5 months (iqr: 0.8-3.9 months). Median followup after ipsilateral recurrence or contralateral primary was 7.76 years (iqr: 3.68-9.81 years). The adjusted hazard ratio for bca death associated with asm was 0.86 (95% confidence limits: 0.63, 1.16). CONCLUSIONS: Annual surveillance mammography was associated with a modestly lowered hazard ratio for bca death.

Temporal association between home nursing and hospital costs at end of life in three provinces.

BACKGROUND: Research has demonstrated that increases in palliative homecare nursing are associated with a reduction in the rate of subsequent hospitalizations. However, little evidence is available about the cost-savings potential of palliative nursing when accounting for both increased nursing costs and potentially reduced hospital costs. METHODS: Our retrospective cohort study included cancer decedents from British Columbia, Ontario, and Nova Scotia who received any palliative nursing in the last 6 months of life. A Poisson regression analysis was used to determine the association of increased nursing costs (in 2-week blocks) on the relative average hospital costs in the subsequent 2-week block and on the overall total cost (hospital costs plus nursing costs in the preceding 2-week block). RESULTS: The cohort included 58,022 cancer decedents. Results of the analysis for the last month of life showed an association between increased nursing costs and decreased relative hospital costs in comparisons with a reference group (>0 to 1 hour nursing in the block): the maximum decrease was 55% for Ontario, 31% for British Columbia, and 38% for Nova Scotia. Also, increased nursing costs in the last month were almost always associated with lower total costs in comparison with the reference. For example, cost savings per person-block ranged from $376 (>10 nursing hours) to $1,124 (>4 to 6 nursing hours) in British Columbia. CONCLUSIONS: In the last month of life, increased palliative nursing costs (compared with costs for >0 to 1 hour of nursing in the block) were associated with lower relative hospital costs and a lower total cost in a subsequent block. Our research suggests a cost-savings potential associated with increased community-based palliative nursing.

Does routine symptom screening with ESAS decrease ED visits in breast cancer patients undergoing adjuvant chemotherapy?

BACKGROUND: In 2007, the provincial cancer agency in Ontario, Canada initiated a wide-scale program to screen for symptoms in the cancer population using the Edmonton Symptom Assessment Scale (ESAS). The purpose of this study is to evaluate the impact of screening with ESAS on emergency department (ED) visit rates in women with breast cancer receiving adjuvant chemotherapy. PATIENTS AND METHODS: This retrospective cohort study used linked administrative health care data from across the province of Ontario, Canada. The cohort included all women aged ≥18 who were diagnosed with stage I-III breast cancer between January 2007 and December 2009 and received adjuvant chemotherapy within 6 months of diagnosis. Using an adjusted recurrent event model, we examined the association of screening with ESAS at a clinic visit on the ED visit rate. RESULTS: The relative rate of ED visits was 0.57 when prior ESAS screening occurred compared to when it did not. The relative rate of ED visits was 0.83 when the prior number of ESAS screens was modeled as a continuous variable. Alternatively stated, the rate of ED visits was 43 % lower among patients previously screened with ESAS compared to those not previously screened. For each additional prior ESAS assessment, there was a 17 % decreased rate of ED visits. CONCLUSIONS: Our results demonstrate that screening with ESAS is associated with decreased ED visits. To our knowledge, this is the first report on the effectiveness of routinely documenting a patient reported outcome on ED visits, in a real-world setting.

Quality of end-of-life cancer care in Canada: a retrospective four-province study using administrative health care data.

BACKGROUND: The quality of data comparing care at the end of life (eol) in cancer patients across Canada is poor. This project used identical cohorts and definitions to evaluate quality indicators for eol care in British Columbia, Alberta, Ontario, and Nova Scotia. METHODS: This retrospective cohort study of cancer decedents during fiscal years 2004-2009 used administrative health care data to examine health service quality indicators commonly used and previously identified as important to quality eol care: emergency department use, hospitalizations, intensive care unit admissions, chemotherapy, physician house calls, and home care visits near the eol, as well as death in hospital. Crude and standardized rates were calculated. In each province, two separate multivariable logistic regression models examined factors associated with receiving aggressive or supportive care. RESULTS: Overall, among the identified 200,285 cancer patients who died of their disease, 54% died in a hospital, with British Columbia having the lowest standardized rate of such deaths (50.2%). Emergency department use at eol ranged from 30.7% in Nova Scotia to 47.9% in Ontario. Of all patients, 8.7% received aggressive care (similar across all provinces), and 46.3% received supportive care (range: 41.2% in Nova Scotia to 61.8% in British Columbia). Lower neighbourhood income was consistently associated with a decreased likelihood of supportive care receipt. INTERPRETATION: We successfully used administrative health care data from four Canadian provinces to create identical cohorts with commonly defined indicators. This work is an important step toward maturing the field of eol care in Canada. Future work in this arena would be facilitated by national-level data-sharing arrangements.

Comparing the Ability of Physician-Reported Versus Patient-Reported Performance Status to Predict Survival in a Population-Based Cohort of Newly Diagnosed Cancer Patients.

AIMS: Performance status is an important prognostic tool in cancer. In oncology, the Eastern Cooperative Oncology Group (ECOG) measure is commonly used. Patient-reported functional status (PRFS) is an emerging method that allows patients to provide an estimate of their function; however, there is limited information about its prognostic significance. The aim of this study was to compare the predictive validity of functional status as reported by patients and physicians in relation to the observed survival after a new cancer diagnosis. MATERIALS AND METHODS: This was a retrospective, population-based study using observational data of newly diagnosed patients in Ontario, Canada. We included patients who had both PRFS and ECOG recorded on the same day during an outpatient cancer clinic visit between March 2013 and March 2018. The dataset was randomly divided into 60% training and 40% validation cohorts. One-year survival was estimated by modelling clinical characteristics with PRFS, with ECOG, and alone. RESULTS: In total, 13 045 patients met the inclusion criteria. Covariates were similar at baseline for both training and validation datasets. PRFS and ECOG scores were statistically significant predictors of overall survival. Higher PRFS and ECOG scores were both associated with inferior survival, hazard ratio = 1.71 (P < 0.0001) and hazard ratio = 1.90 (P < 0.0001), respectively. Models that included either PRFS or ECOG scores outperformed the model with clinical characteristics only. C statistics were 0.836, 0.839 and 0.811, respectively. CONCLUSIONS: PRFS adds to survival modelling and is equally predictive as the ECOG scale. PRFS may be used instead of ECOG in clinical or research settings for survival estimation.

Exposure to maternal depressive symptoms in childhood and adolescent suicide-related thoughts and attempts: mediation by child psychiatric symptoms.

AIMS: The nature of the association between child psychiatric symptoms and adolescent suicide-related thoughts (SRT) and attempts (SA) remains unclear. Our objective was to assess whether child psychiatric symptoms from 6 to 10 years of age mediate the association between exposure to maternal depressive symptoms in childhood and offspring SRT and SA in adolescence. METHODS: A population-based cohort study was constructed by linking all eight cycles from the National Longitudinal Survey of Children and Youth (NLSCY), a nationally representative Canadian panel survey conducted from 1994 to 2009. Self-reported maternal depressive symptoms were measured when offspring were between 0 and 5 years. Maternal-reported child psychiatric symptoms and psychiatric comorbid symptoms were measured from 6 to 10 years, and offspring self-reported SRT and SA were measured between 11 and 19 years. Indirect effects, the effect proportion mediated and their corresponding bootstrapped 95% confidence intervals (CI) were estimated. RESULTS: Hyperactivity and inattention significantly mediated the association between maternal depressive symptoms in childhood and risk of both SRT and SA from 11 to 19 years, where approximately 60% (SRT 95% CI 23-94%; SA 95% CI 27-95%) of this association was explained by hyperactivity and inattention. Psychiatric comorbid symptoms also significantly mediated this relationship and accounted for 50% (95% CI 18-81%) of this association with SA. CONCLUSIONS: Targeting hyperactivity and inattention, and co-occurring psychiatric symptoms in offspring of depressed mothers could reduce risk of SRT, eventual SA and halt progression towards suicide. However, further understanding of comorbid psychiatric symptoms in childhood that most strongly predict adolescent SA is needed.

Factors associated with receipt of symptom screening in the year after cancer diagnosis in a universal health care system: a retrospective cohort study.

Purpose: Patient-reported symptom data are collected prospectively by a provincial cancer agency to mitigate the significant symptom burden that patients with cancer experience. However, an assessment of whether such symptom screening occurs uniformly for those patients has yet to be performed. In the present study, we investigated patient, disease, and health system factors associated with receipt of symptom screening in the year after a cancer diagnosis. Methods: Patients diagnosed with cancer between 2007 and 2014 were identified. We measured whether 1 or more symptom screenings were recorded in the year after diagnosis. A multivariable modified Poisson regression with robust error variance was used to identify predictors [age, comorbidity, rurality, socioeconomic status, immigration status, cancer site, registration at a regional cancer centre (cc), and year of diagnosis] of being screened for symptoms. Results: Of 425,905 patients diagnosed with cancer, 163,610 (38%) had 1 or more symptom screening records in the year after diagnosis, and 75% survived at least 1 year. We identified variability in symptom screening by primary cancer site, regional cc, age, sex, comorbidity, material deprivation, rurality of residence, and immigration status. Patients who had been diagnosed with melanoma or endocrine cancers, who were not registered at a regional cc, who lived in the most urban areas, who were elderly, and who were immigrants were least likely to undergo symptom screening after diagnosis. Conclusions: Our evaluation of the implementation of a population-based symptom screening program in a universal health care system identified populations who are at risk for not receiving screening and who are therefore future targets for improvements in population symptom screening and better management of cancer-related symptoms at diagnosis.

Risk of contralateral lower limb amputation and death after initial lower limb amputation - a population-based study.

BACKGROUND: Lower limb amputation (LLA) is a complication of lower limb atherosclerosis, infection and tissue gangrene. Following ipsilateral LLA, the risk of major amputation of the contralateral limb or of death is unknown. The aim of this study was to determine the incidence of a contralateral major LLA, comparing those with a non-malignant/non-traumatic ipsilateral major vs. ipsilateral minor LLA. METHODS: We used pre-existing linked administrative health databases for the study. Data were provided by the Institute for Clinical Evaluation Sciences (ICES), Toronto, Ontario. This is a retrospective population-based cohort study across Ontario, Canada, 2002-2012. Cause-specific Cox regression models were used to obtain hazard ratios. Cumulative incidence functions were used to calculate the risk of contralateral major LLA and the risk of the competing event death. Individuals who did not survive at least 30 days after their first ipsilateral LLA were excluded since they were ineligible to have a contralateral LLA. RESULTS: 5,816 adults underwent an ipsilateral major and 4,143 an ipsilateral minor LLA. The incidences of contralateral major LLA were 4.8 and 2.2 (adjusted HR 2.41, 95% CI 2.04-2.84) after ipsilateral major and minor LLA, respectively. Incidence of death was 18.9 and 11.4 (adjusted HR 1.22, 95% CI 1.13-1.31) following ipsilateral major and minor LLA, respectively. CONCLUSION: There is high incidence of a contralateral major LLA and even higher risk of death following the ipsilateral LLA. Healthcare professionals should develop strategies for contralateral limb preservation in individuals with existing ipsilateral LLA.

Contralateral prophylactic mastectomy in young women with breast cancer: a population-based analysis of predictive factors and clinical impact.

Background and Objectives: Contralateral prophylactic mastectomy (cpm) has been increasingly common among women with unilateral invasive breast cancer (ibca) even though the data that support it are limited. Using a population-based cohort, the objectives of the present study were to describe factors predictive of cpm in young women (≤35 years) with ibca and to evaluate the impact of the procedure on mortality. Methods: All women diagnosed during 1994-2003 and treated with cpm were identified from the Ontario Cancer Registry. Logistic regression was used to identify patient and tumour factors associated with the use of cpm. Multivariate analyses were used to assess the effect of cpm on recurrence and mortality. Results: Of 614 women identified, 81 underwent cpm (13.2%). On multivariable analysis, factors associated with cpm included negative lymph node status, negative estrogen receptor status, and initial breast-conserving surgery with re-excision. At follow-up, breast cancer-specific mortality was similar for women who did and did not undergo cpm. Conclusions: Use of cpm in young women with ibca (compared with non-use) was not associated improved breast cancer-specific mortality. Factors found to be predictive of cpm were negative lymph node status, negative estrogen receptor status, and initial breast-conserving surgery followed by re-excision.

Factors associated with imaging in patients with early breast cancer after initial treatment.

Background: Overuse of surveillance imaging in patients after curative treatment for early breast cancer (ebc) was recently identified as one of the Choosing Wisely Canada initiatives to improve the quality of cancer care. We undertook a population-level examination of imaging practices in Ontario as they existed before the launch of that initiative. Methods: Patients diagnosed with ebc between 2006 and 2010 in Ontario were identified from the Ontario Cancer Registry. Records were linked deterministically to provincial health care databases to obtain comprehensive follow-up. We identified all advanced imaging exams [aies: computed tomography (ct), bone scan, positron-emission tomography] and basic imaging exams (bies: ultrasonography, chest radiography) occurring within the first 2 years after curative treatment. Poisson regression was used to assess associations between patient or provider characteristics and the rate of aies. Results: Of 30,006 women with ebc, 58.6% received at least 1 bie, and 30.6% received at least 1 aie in year 1 after treatment. In year 2, 52.7% received at least 1 bie, and 25.7% received at least 1 aie. The most common aies were chest cts and bone scans. The rate of aies increased with older age, higher disease stage, comorbidity, chemotherapy exposure, and prior staging investigations (p < 0.001). Imaging was ordered mainly by medical oncologists (38%), followed by primary care physicians (23%), surgeons (13%), and emergency room physicians (7%). Conclusions: Despite recommendations against its use, imaging is common in ebc survivors. Understanding the factors associated with aie use helps to identify areas for further research and is required to lower imaging rates and to improve survivorship care.

Multistate transitional models for measuring adherence to breast cancer screening: A population-based longitudinal cohort study with over two million women.

Objective Prior work on the disparities among women in breast cancer screening adherence has been methodologically limited. This longitudinal study determines and examines the factors associated with becoming adherent. Methods In a cohort of Canadian women aged 50-74, a three-state transitional model was used to examine adherence to screening for breast cancer. The proportion of time spent being non-adherent with screening was calculated for each woman during her observation window. Using age as the time scale, a relative rate multivariable regression was implemented under the three-state transitional model, to examine the association between covariates (all time-varying) and the rate of becoming adherent. Results The cohort consisted of 2,537,960 women with a median follow-up of 8.46 years. Nearly 31% of women were continually up-to-date with breast screening. Once a woman was non-adherent, the rate of becoming adherent was higher among longer term residents (relative rate = 1.289, 95% confidence interval 1.275-1.302), those from wealthier neighbourhoods, and those who had an identifiable primary care provider who was female or had graduated in Canada. Conclusion Individual and physician-level characteristics play an important role in a woman's adherence to screening. This work improves the quality of evidence regarding disparities among women in adherence to breast cancer screening and provides a novel methodological foundation to investigate adherence for other types of screening, including cervix and colorectal cancer screening.

The association between visiting a primary care provider and uptake of periodic mammograms as women get older.

OBJECTIVE: To determine whether visits to a primary care provider (PCP) are associated with the uptake of periodic mammograms as women get older. METHODS: The cohort consisted of 2,389,889 women resident in Ontario, Canada, aged 50 to 79 at any point from 2001 to 2010, who were cancer-free and eligible for the Ontario Health Insurance Plan prior to study entry. Non-parametric estimation was used to describe the mean cumulative number of periodic mammograms for women with and without recent exposure to a PCP, as a function of age. Using age as the time scale, a recurrent event regression model was also implemented to examine the association between exposure to a PCP and rate of periodic mammograms, adjusted for income quintile and comorbidity. RESULTS: The mean observation window was 7.0 years. Uptake of periodic mammograms was significantly higher for women with recent exposure to a PCP compared with those without. This trend remained consistent as women aged, and the magnitude of the association increased for women aged 65 or older. The relative rate of periodic mammograms was lower than 1 and consistently decreased as women from lower income quintiles were compared with women from the wealthiest quintile. CONCLUSION: Visits to a PCP play an important role in uptake of periodic mammograms, and this association increases as women age.