Effectiveness of post-COVID-19 primary care attendance in improving survival in very old patients with multimorbidity: a territory-wide target trial emulation.

ABSTRACT

BACKGROUND: Older adults with multimorbidity are at high risk of mortality following COVID-19 hospitalisation. However, the potential benefit of timely primary care follow-up on severe outcomes post-COVID-19 has not been well established. AIM: To examine the effectiveness of attending general outpatient within 30 days after discharge from COVID-19 on 1-year survival among older adults aged ≥85 years, with multimorbidity. METHOD: We emulated a target trial using a comprehensive public healthcare database in Hong Kong. The cloning-censoring-weighting technique was used to minimise immortal time bias and confounding bias by adjusting for demographics, hospitalisation duration and ICU admission, baseline chronic conditions, and medication history. The outcome included all-cause and cause-specific mortality. RESULTS: Of 6183 eligible COVID-19 survivors, the all-cause mortality rate following COVID-19 hospitalisation was lower in general out-patient clinics (GOPC) group compared to non-GOPC group (17.1 versus 42.8 deaths per 100 person-year). After adjustment, primary care consultations within 30 days after discharge were associated with a significantly greater 1-year survival (difference in 1-year survival 11.2%, 95% CI = 8.1% to 14.4%). We also observed better survival from respiratory diseases in the GOPC group. In a sensitivity analysis for different grace period lengths, we found that the earlier participants had a GOPC visit after COVID-19 discharge, the better the survival. CONCLUSION: Timely primary care consultations after discharge may improve survival following COVID-19 hospitalisation among older adults aged ≥85 years, with multimorbidity. Expanding primary care services and implementing follow-up mechanisms are crucial to support this vulnerable population's recovery and well-being.