Table 4

Associations of mortality with patterns of medication use among hospitalised VA patients with COVID-19 followed for 60 days, estimated from propensity score weighted proportional hazards models

aHR*95% Confidence limits
ACE-I
Before only1.391.24 to 1.57
After only0.240.14 to 0.39
Before and after†
≤40 days0.730.63 to 0.84
>40 days0.790.50 to 1.24
ARB
Before only‡
≤25 days1.971.67 to 2.32
>25 days1.170.73 to 1.88
After only0.530.33 to 0.84
Before and after§
≤20 days0.650.52 to 0.81
>20 days1.421.09 to 1.83
Metformin
Before only¶
≤25 days1.531.32 to 1.77
>25 days1.881.43 to 2.47
After only0.200.07 to 0.54
Before and after0.280.21 to 0.37
  • *aHRs are estimated using inverse propensity score weighted Cox proportional hazards models adjusted for: age, race, ethnicity, sex, overweight and smoking status at index date, and for the for the presence of the following pre-existing conditions within 2 years of positive COVID-19 test: diabetes (type 2), CVD, HTN, CAHD, CHF, mention of heart disease, mention of heart failure, COPD, bronchitis, acute respiratory failure, asthma, mention of chronic lung disease and emphysema, and for the CCI, and fitted with time dependent terms for medication categories, where statistically indicated. Propensity scores were derived from multinomial logistic regression predicting probability of being in a medication treatment category using morbidity that would indicate clinical need for treatment. Death is death from any cause within 60 days of COVID-19 positive test result. Time dependence was tested using product terms for each medication category×log (−log(survival time)) at p <0.05. For time dependent medication categories, risk was estimated from models stratified by survival time. The stratification time points were selected based on examination of survival curves, log(−log survival)) curves and by calculating contrasts at 5-day intervals to determine where estimated associations became non-statistically significant or diverged.

  • †P(ACE-I: before and after×log (−log(survival)))=0.0451.

  • ‡P(ARB: before only×log (−log(survival)))=0.0267.

  • §P(ARB: before and after×log (−log(survival)))<0.0001.

  • ¶P(metformin: before only×log(−log(survival)))=0.0002.

  • aHRs, adjusted HRs; CAHD, coronary atherosclerotic heart disease; CCI, Charlson Comorbidity Index; CHF, congestive heart failure; COPD, chronic obstructive pulmonary disease; CVD, cardiovascular disease; HTN, hypertension; VA, Veterans Affairs.