Importance of accounting for loss to follow-up when comparing mortality between immigrants and long-term residents: a population-based retrospective cohort

OBJECTIVES

To evaluate the association between immigration status and all-cause mortality in different disease cohorts, and the impact of loss to follow-up on the observed associations.

DESIGN

Population-based retrospective cohort study using linked administrative health data in Ontario, Canada.

SETTING

We followed adults with a first-ever diagnosis of ischaemic stroke, cancer or schizophrenia between 2002 and 2013 from index event to death, loss to follow-up, or end of follow-up in 2018.

PRIMARY AND SECONDARY OUTCOME MEASURES

Our outcomes of interest were all-cause mortality and loss to follow-up. For each disease cohort, we calculated adjusted HRs of death in immigrants compared with long-term residents, adjusting for demographic characteristics and comorbidities, with and without censoring for those who were lost to follow-up. We calculated the ratio of two the HRs and the respective CL using bootstrapping methods.

RESULTS

Immigrants were more likely to be lost to follow-up than long-term residents in all disease cohorts. Not accounting for this loss to follow-up overestimated the magnitude of the association between immigration status and mortality in those with ischaemic stroke (HR of death before vs after accounting for censoring: 0.78 vs 0.83, ratio=0.95; 95% CL 0.93 to 0.97), cancer (0.74 vs 0.78, ratio=0.96; 0.95 to 0.96), and schizophrenia (0.54 vs 0.56, ratio=0.97; 0.96 to 0.98).

CONCLUSIONS

Immigrants to Canada have a survival advantage that varies by the disease studied. The magnitude of this advantage is modestly overestimated by not accounting for the higher loss to follow-up in immigrants.

Are quality improvement plans perceived to improve the quality of primary care in Ontario? Qualitative study

OBJECTIVE

To explore primary care administrators' perceptions of provincially mandated quality improvement plans, and barriers to and facilitators of using quality improvement plans as tools for improving the quality of primary care.

DESIGN

Qualitative descriptive study using semistructured interviews.

SETTING

Ontario.

PARTICIPANTS

Eleven primary care administrators (ie, executive directors, director of clinical services, office administrators) at 7 family health teams and 4 community health centres.

METHODS

All interviews were audiotaped and transcribed verbatim. Data were analyzed deductively to generate a framework based on a conceptual model of structural, organizational, individual, and innovation-related factors that influence the success of improvement initiatives and, inductively, to generate additional themes.

MAIN FINDINGS

Provincially mandated quality improvement plans seem to have raised awareness of and provided an overall focus on quality improvement, and have contributed to primary care organizations implementing initiatives to address quality gaps. Four factors that have contributed to the success of quality improvement plans relate to attributes of the quality improvement plans (adaptability and compatibility) and contextual factors (leadership and organizational culture). However, participants expressed that the use of quality improvement plans have not yet led to substantial improvements in the quality of primary care in Ontario, which may be owing to several challenges: poor data quality, lack of staff and physician engagement and buy-in, and lack of resources to support measurement and quality improvement.

CONCLUSION

Awareness of and focused attention on the need for high-quality patient care may have increased, but participants expressed that substantial improvements in quality care have yet to be achieved in Ontario. The lack of perceived improvements is likely the result of multifaceted and complex challenges primary care organizations face when trying to improve patient care. To effect positive change, organization- and health system-level efforts are needed to improve measurement capabilities, improve staff and physician engagement, and increase capacity for quality improvement among organizations.

Incidence of Stroke in Immigrants to Canada: A Province-wide Retrospective Analysis

BACKGROUND AND OBJECTIVES

To evaluate the association between immigration status and stroke incidence.

METHODS

We conducted a retrospective cohort study of 8 million adults (15% immigrants) residing in Ontario, Canada, on January 1, 2003, with no history of stroke or TIA. Participants were followed up until March 31, 2018, to identify incident stroke or TIA, defined as hospitalization or emergency room visit. We calculated adjusted hazard ratios (HRs) of stroke or TIA in immigrants compared to long-term residents using cause-specific hazard models, adjusting for demographics and comorbid conditions. We evaluated whether the association varied by age, stroke type, or country of origin of immigrants.

RESULTS

During 109 million person-years of follow-up, we observed 235,336 incident stroke or TIA events. Compared to long-term residents, immigrants had a lower rate of stroke or TIA (10.9 vs 23.4 per 10,000 person-years, HR 0.67, 95% confidence interval [CI] 0.66-0.68). This was true across all age groups and stroke types, with an HR in immigrants vs long-term residents for ischemic stroke of 0.71 (95% CI 0.69-0.72), for intracerebral hemorrhage of 0.89 (95% CI 0.85-0.93), for subarachnoid hemorrhage of 0.85 (95% CI 0.81-0.91), and for TIA of 0.53 (95% CI 0.51-0.54). The magnitude of the reduction in stroke risk associated with immigration status was less pronounced in immigrants from the Caribbean (HR 0.95, 95% CI 0.91-1.00), Latin America (HR 0.85, 95% CI 0.82-0.91), and Africa (HR 0.80, 95% CI 0.74-0.85) than in those from other world regions.

DISCUSSION

Immigrants have a lower rate of stroke or TIA than long-term residents with variation by age, stroke type, and country of origin. This knowledge may be useful for developing targeted primary stroke prevention strategies.

Partnering with survivors & families to determine research priorities for adult out-of-hospital cardiac arrest: A James Lind Alliance Priority Setting Partnership

BACKGROUND

Research priority setting in health care has historically been done by expert health care providers and researchers and has not involved patients, family or the public. Survivors & family members have been particularly absent from this process in the field of resuscitation research and specifically adult out of hospital cardiac arrest (OHCA). As such, we sought to conduct a priority setting exercise in partnership with survivors, lay responders and their families in order to ensure that their priorities were visible. We partnered with the James Lind Alliance (UK) and used their commonly used consensus methodology for Public Priority Setting Partnerships (PSPs) to identify research priorities that reflected the perspectives of all stakeholders.

METHODS

We used two rounds of public and health care professional surveys to create the initial priority lists. The initial survey collected open-ended questions while the second round consolidated the list of initial questions into a refined list for prioritization. This was done by reviewing existing evidence and thematic categorization by the multi-disciplinary steering committee. An in-person consensus workshop was conducted to come to consensus on the top ten priorities from all perspectives. The McMaster PPEET tool was used to measure engagement.

RESULTS

The initial survey yielded more than 425 responses and 1450 "questions" from survivors and family members (18%), lay responders, health care providers and others. The second survey asked participants to rank a short list of 125 questions. The final top 25 questions were brought to the in-person meeting, and a top ten were selected through the JLA consensus process. The final list of top ten questions included how to improve the rate of lay responder CPR, what interventions used at the scene of an arrest can improve resuscitation and survival, how survival can be improved in rural areas of Canada, what resuscitation medications are most effective, what care patient's family members need, what post-discharge support is needed for survivors, how communication should work for everyone involved with a cardiac arrest, what factors best predict neurologically intact survival, whether biomarkers/genetic tests are effective in predicting OHCA and more research on the short and long-term psycho-social impacts of OHCA on survivors. The PPEET showed overwhelmingly positive results for the patient and family engagement experience during the final workshop.

CONCLUSIONS

This inclusive research priority setting provides essential information for those doing resuscitation research internationally. The results provide a guide for priority areas of research and should drive our community to focus on questions that matter to survivors and their families in our work. In particular the Canadian Resuscitation Outcomes Consortium will be incorporating the top ten list into its strategic plan for the future.

External Validation and Modification of Nationwide Inpatient Sample Subarachnoid Hemorrhage Severity Score

BACKGROUND

The Nationwide Inpatient Sample Subarachnoid Hemorrhage (SAH) Severity Score (NIS-SSS) was developed as a measure of SAH severity for use in administrative databases. The NIS-SSS consists of International Classification of Diseases Ninth Revision (ICD-9) diagnostic and procedure codes derived from the SAH inpatient course and has been validated against the Hunt-Hess score (HH).

OBJECTIVE

To externally validate both the NIS-SSS and a modified version of the NIS-SSS (m-NIS-SSS) consisting of codes present only on admission, against the HH in a Canadian province-wide registry and administrative database of SAH patients.

METHODS

A total of 1467 SAH patients admitted to Ontario stroke centers between 2003 and 2013 with recorded HH were included. The NIS-SSS and m-NIS-SSS were validated against the HH by testing correlation between the NIS-SSS/m-NIS-SSS and HH, comparing discriminative ability of the NIS-SSS/m-NIS-SSS vs HH for poor outcome by calculating area under the curve (AUC), and comparing calibration of the NIS-SSS, m-NIS-SSS, and HH by plotting predicted vs observed outcome.

RESULTS

Correlation with HH was 0.417 (P ≤ .001) for NIS-SSS, and 0.403 (P ≤ .001) for m-NIS-SSS. AUC for prediction of poor outcome was 0.786 (0.764-0.808) for HH, 0.771 (0.748-0.793) for NIS-SSS, and 0.744 (0.721-0.767) for m-NIS-SSS. Calibration plots demonstrated that HH had the most accurate prediction of outcome, whereas the NIS-SSS and m-NIS-SSS did not accurately predict low risk of poor outcome.

CONCLUSION

The NIS-SSS and m-NIS-SSS have good external validity, and therefore, may be suitable to approximate traditional clinical scores of disease severity in SAH research using administrative data.

Adherence at 2 years with distribution of essential medicines at no charge: The CLEAN Meds randomized clinical trial

BACKGROUND

Adherence to medicines is low for a variety of reasons, including the cost borne by patients. Some jurisdictions publicly fund medicines for the general population, but many jurisdictions do not, and such policies are contentious. To our knowledge, no trials studying free access to a wide range of medicines have been conducted.

METHODS AND FINDINGS

We randomly assigned 786 primary care patients who reported not taking medicines due to cost between June 1, 2016 and April 28, 2017 to either free distribution of essential medicines (n = 395) or to usual medicine access (n = 391). The trial was conducted in Ontario, Canada, where hospital care and physician services are publicly funded for the general population but medicines are not. The trial population was mostly female (56%), younger than 65 years (83%), white (66%), and had a low income from wages as the primary source (56%). The primary outcome was medicine adherence after 2 years. Secondary outcomes included control of diabetes, blood pressure, and low-density lipoprotein (LDL) cholesterol in patients taking relevant treatments and healthcare costs over 2 years. Adherence to all appropriate prescribed medicines was 38.7% in the free distribution group and 28.6% in the usual access group after 2 years (absolute difference 10.1%; 95% confidence interval (CI) 3.3 to 16.9, p = 0.004). There were no statistically significant differences in control of diabetes (hemoglobin A1c 0.27; 95% CI -0.25 to 0.79, p = 0.302), systolic blood pressure (-3.9; 95% CI -9.9 to 2.2, p = 0.210), or LDL cholesterol (0.26; 95% CI -0.08 to 0.60, p = 0.130) based on available data. Total healthcare costs over 2 years were lower with free distribution (difference in median CAN$1,117; 95% CI CAN$445 to CAN$1,778, p = 0.006). In the free distribution group, 51 participants experienced a serious adverse event, while 68 participants in the usual access group experienced a serious adverse event (p = 0.091). Participants were not blinded, and some outcomes depended on participant reports.

CONCLUSIONS

In this study, we observed that free distribution of essential medicines to patients with cost-related nonadherence substantially increased adherence, did not affect surrogate health outcomes, and reduced total healthcare costs over 2 years.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02744963.

Immigration Status, Ethnicity, and Long-term Outcomes Following Ischemic Stroke

OBJECTIVE

To assess the association between immigration status and ethnicity and the outcomes of mortality and vascular event recurrence following ischemic stroke in Ontario, Canada.

METHODS

We conducted a retrospective cohort study using linked administrative and clinical registry-based data from 2002 to 2018 and compared hazards of all-cause mortality and vascular event recurrence in immigrants and long-term residents using inverse probability of treatment weighting accounting for age, sex, income, and comorbidities. We stratified analyses by age (≤75 and >75 years) and used interaction terms to evaluate whether the association between immigration status and outcomes varied with age or ethnicity.

RESULTS

We followed 31,918 adult patients, of whom 2,740 (8.6%) were immigrants, for a median follow-up of 5 years. Immigrants had lower mortality than long-term residents (46.1% vs 64.5%), which was attenuated after adjustment (hazard ratio [HR] 0.94; 95% confidence interval [CI] 0.88-1.00), but persisted in those younger than 75 years (HR 0.82; 0.74-0.91). Compared to their respective ethnic long-term resident counterparts, the adjusted hazard of death was higher in South Asian immigrants, similar in Chinese immigrants, and lower in other immigrants (p value for interaction = 0.003). The adjusted hazard of vascular event recurrence (HR 1.01; 0.92-1.11) was similar in immigrants and long-term residents, and this observation persisted across all age and ethnic groups.

CONCLUSIONS

Long-term mortality following ischemic stroke is lower in immigrants than in long-term residents, but is similar after adjustment for baseline characteristics, and it is modified by age at the time of stroke and by ethnicity.

Stroke Incidence by Sex Across the Lifespan

BACKGROUND AND PURPOSE

We evaluated the influence of age on the association between sex and the incidence of stroke or transient ischemic attack (TIA) using a population-based cohort from Ontario, Canada.

METHODS

We followed a cohort of adults (≥18 years) without prior stroke from January 1, 2003 (cohort start date) to March 31, 2018, to identify incident events. We calculated hazard ratios (HRs), in women compared to men, of incident stroke or TIA, adjusted for demographics and comorbidities, overall and stratified by stroke type. We calculated piecewise adjusted HRs for each decade of age to evaluate the effect of age on sex differences in stroke incidence.

RESULTS

We followed 9.2 million adults for a median of 15 years and observed 280,197 incident stroke or TIA events. Compared with men, women had an overall lower adjusted hazard of stroke or TIA (HR, 0.82 [95% CI, 0.82-0.83]), with similar findings across all stroke types except for subarachnoid hemorrhage (HR, 1.29 [95% CI, 1.24-1.33]). We found a U-shaped association between age and sex differences in the incidence of stroke or TIA: compared with men, the hazard of stroke was higher in women among those aged ≤30 years (HR, 1.26 [95% CI, 1.10-1.45]), lower among those between ages 40 and 80 years (eg, age 50-59, HR, 0.69 [95% CI, 0.68-0.70]), and similar among those aged ≥80 years (HR, 0.99 [95% CI, 0.98-1.01]).

CONCLUSIONS

Overall, women have a lower hazard of stroke than men, but this association varies by age and across stroke types. Recognition of age-sex variations in stroke incidence can help guide prevention efforts to reduce stroke incidence in both men and women.