The impact of multimorbidity on short-term events in patients with community-acquired pneumonia: prospective cohort study

The impact of multimorbidity on patients with community-acquired pneumonia has not been well characterised. Thus, our aim was to explore the relationship between multimorbidity and adverse events within 90 days of discharge. Data were prospectively collected for a population-based cohort of all adults discharged from any of the seven emergency departments (ED) or six hospitals in Edmonton (Alberta, Canada) with community-acquired pneumonia. Multivariable Cox regression models were used to examine the independent association between multimorbidity (defined as two or more chronic conditions) and subsequent 90-day mortality, hospitalisation, or ED visits after treatment of pneumonia. The cohort included 5565 patients, mean age was 57 years (SD 20), 54% were male, and 59% were treated as outpatients; 1602 (29%) patients had multimorbidity. Within 90 days, 255 (5%) patients died, 1205 (22%) were hospitalised, 1280 (23%) died or were hospitalised, and 2049 (37%) were admitted to the ED. The presence of multimorbidity was independently associated with an increased risk of death or hospitalisation within 90 days (37% vs. 17% for those without multimorbidity, adjusted hazard ratio: 1.43, 95% confidence interval: 1.26 to 1.62) as well as ED visits (45% vs. 34%, adjusted hazard ratio: 1.40, 95% confidence interval: 1.26 to 1.56). Multimorbidity was present in one-third of all patients with pneumonia in our study, and it was independently associated with death, hospitalisation, or return to ED within 90 days of discharge. Our findings suggest that multimorbidity is strongly related to prognosis and should be considered when making site-of-care decisions in the ED or deciding upon readiness for discharge.