Date of Award

January 2024

Document Type

Thesis

Degree Name

Medical Doctor (MD)

Department

Medicine

First Advisor

Joseph S. Ross

Abstract

Background: A large proportion of stroke cases are attributable to modifiable vascular risk factors such as diabetes, hyperlipidemia, and hypertension. Treatment and control of vascular risk factors are an integral part of primary and secondary prevention of stroke. Despite major progress in stroke prevention, treatment gaps persist, both within the U.S. and internationally. We focused on potential gaps in primary stroke prevention in China, and in secondary stroke prevention in the U.S. First, among people in China who had hypertension, we assessed the association of primary care clinics’ institutional characteristics with hypertension awareness, treatment, and control. Second, among people in the U.S. who were survivors of stroke, we examined the associations between disability status and treatment and control of diabetes, hyperlipidemia, and hypertension.

Methods: First, we used data from the China Patient-centered Evaluative Assessment of Cardiac Events (PEACE) Million Persons Project (MPP). We linked primary care institution characteristics that were captured in the survey between 2016 and 2017 to the participant-level data gathered in baseline visits between 2014 and 2021. To estimate the associations between primary care institutional characteristics with hypertension awareness, treatment, and control, we created three multi-level (participant-level and institution-level) logistic models. Second, in a cross-sectional analysis of the 2011-2018 National Health and Nutrition Examination Survey, we compared diabetes, hyperlipidemia, and hypertension treatment and control rates among self-reported survivors of stroke age ≥20 years with and without disabilities, defined as having a disability in any of five physical or four functional domains in a structured questionnaire. To estimate associations between disability status and risk factor treatment and control, we used logistic regression models adjusted for age, gender, race and ethnicity, and history of medical conditions.

Results: In the China PEACE-MPP sample, we analyzed 433 township-level primary care institutions across all 31 provinces of mainland China, including 660565 individuals with hypertension in their catchment areas. Across townships, age-sex standardized hypertension awareness varied from 8.2% to 81.0%, treatment varied from 2.6% to 96.5%, and control proportions varied from 0% to 62.4%. Hypertension awareness, treatment, and control were significantly associated with the following institutional characteristics: government funding through balance allocation (awareness odds ratio (OR) 0.88, 95% CI, 0.78–0.99; p=0.027), having financial problems that interrupted routine service delivery (awareness OR 0.81, 0.72–0.92; p=0.0007, control OR 0.84; 0.75–0.94, p=0.0034), setting performance-based bonus (treatment OR 1.39, 1.07–1.80; p=0.013), basic salary defined by number of patient visits (control OR 0.85, 0.76–0.95; p=0.0053), using electronic referrals (treatment OR 1.41, 1.14–1.73; p=0.0012, control OR 1.17; 1.03–1.33, p=0.014), implementing family physician contract services (awareness OR 1.13, 1.00–1.28; p=0.045, control OR 1.30; 1.15–1.46, p<0.0001), and proportion of physicians who are formally licensed (awareness per 10% increase OR 1.04, 1.01–1.08; p=0.019, treatment OR 1.08; 1.02–1.14, p=0.0077; control per 10% increase OR 1.07, 1.03–1.10; p=0.0006). In the U.S. sample, the mean age of survivors of stroke was 65.1 years and 55.5% were female; 76% (95% CI, 72.7-79.3) self-reported at least one disability. Age-standardized treatment rates for diabetes, hyperlipidemia, and hypertension were 33.1% (95% CI, 26.9-39.2), 67.5% (95% CI, 62.6-72.3), and 78.4% (95% CI, 74.6-82.2). Age-standardized control rates for diabetes, hyperlipidemia, and hypertension were 86.8% (95% CI, 83.8-89.8), 20.5% (95% CI, 15.0-25.9), and 47.1% (95% CI, 42.6-51.7). In adjusted models, those with and without disabilities had no significant difference in the odds of risk factor treatment and control.

Conclusion: In China, gaps remain in the quality of stroke primary prevention through hypertension management, especially in primary care’s institutional financing, performance appraisal, service delivery, and information technology. In the U.S., three-quarters of survivors of stroke self-reported a disability, and these patients had no significant difference in odds of diabetes, hyperlipidemia, and hypertension treatment and control compared to those without disability.

Comments

This thesis is restricted to Yale network users only. This thesis is permanently embargoed from public release.

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