Association of Reduction in Continuity of Care During COVID ‐19 Pandemic With Cardiovascular Diseases, Kidney Failure and All‐Cause Mortality for People With Diabetes: A Cohort Study in Hong Kong

Introduction Continuity of care, a critical component of high‐quality primary care, was interrupted in people with diabetes mellitus during the COVID‐19 pandemic in Hong Kong. Research on whether reduced continuity of care was associated with higher complications and mortality risks is lacking. Methods This retrospective cohort study included 123 403 eligible adult patients with diabetes. Continuity of care was assessed by the usual provider continuity index (UPCI), calculated as the proportion of attendances to the patients' most visited clinic during both pre‐outbreak period (August 2017–December 2019) and outbreak period (January 2020–May 2022). Patients were followed from 1 June 2022 until the outcomes of interest or June 2024. Cox regression was applied to evaluate the association between reduced continuity of care and risks of incident cardiovascular diseases (CVD), kidney failure and all‐cause mortality. Results Greater reductions in UPCI were associated with higher risks of CVD; the hazard ratios (HR, 95% CI) for 10%–20% reduction were 1.05 (0.97, 1.14), HR = 1.33 (1.14, 1.56) for 20%–30% reduction, and HR = 1.30 (1.14, 1.48) for 30% reduction when compared to patients experiencing ≤ 10% reduction in UPCI. Similar patterns were found for CVD subtypes, including coronary heart disease and heart failure. Reductions of 20%–30% and > 30.1% in UPCI were associated with higher kidney failure risks. Conclusion Greater impairment in continuity of care was associated with increased incidences of CVD in diabetic patients. Our results emphasize the need for health policies to have contingency plans for maintaining continuity of primary care for patients with DM in future public health crises.