Risk Factors Associated With All-Cause 30-Day Mortality in Nursing Home Residents With COVID-19

Abstract

Importance: The coronavirus disease 2019 (COVID-19) pandemic has severely affected nursing homes. Vulnerable nursing home residents are at high risk for adverse outcomes, but improved understanding is needed to identify risk factors for mortality among nursing home residents.

Objective: To identify risk factors for 30-day all-cause mortality among US nursing home residents with COVID-19.

Design, setting, and participants: This cohort study was conducted at 351 US nursing homes among 5256 nursing home residents with COVID-19-related symptoms who had severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection confirmed by polymerase chain reaction testing between March 16 and September 15, 2020.

Exposures: Resident-level characteristics, including age, sex, race/ethnicity, symptoms, chronic conditions, and physical and cognitive function.

Main outcomes and measures: Death due to any cause within 30 days of the first positive SARS-CoV-2 test result.

Results: The study included 5256 nursing home residents (3185 women [61%]; median age, 79 years [interquartile range, 69-88 years]; and 3741 White residents [71%], 909 Black residents [17%], and 586 individuals of other races/ethnicities [11%]) with COVID-19. Compared with residents aged 75 to 79 years, the odds of death were 1.46 (95% CI, 1.14-1.86) times higher for residents aged 80 to 84 years, 1.59 (95% CI, 1.25-2.03) times higher for residents aged 85 to 89 years, and 2.14 (95% CI, 1.70-2.69) times higher for residents aged 90 years or older. Women had lower risk for 30-day mortality than men (odds ratio [OR], 0.69 [95% CI, 0.60-0.80]). Two comorbidities were associated with mortality: diabetes (OR, 1.21 [95% CI, 1.05-1.40]) and chronic kidney disease (OR, 1.33 [95%, 1.11-1.61]). Fever (OR, 1.66 [95% CI, 1.41-1.96]), shortness of breath (OR, 2.52 [95% CI, 2.00-3.16]), tachycardia (OR, 1.31 [95% CI, 1.04-1.64]), and hypoxia (OR, 2.05 [95% CI, 1.68-2.50]) were also associated with increased risk of 30-day mortality. Compared with cognitively intact residents, the odds of death among residents with moderate cognitive impairment were 2.09 (95% CI, 1.68-2.59) times higher, and the odds of death among residents with severe cognitive impairment were 2.79 (95% CI, 2.14-3.66) times higher. Compared with residents with no or limited impairment in physical function, the odds of death among residents with moderate impairment were 1.49 (95% CI, 1.18-1.88) times higher, and the odds of death among residents with severe impairment were 1.64 (95% CI, 1.30-2.08) times higher.

Conclusions and relevance: In this cohort study of US nursing home residents with COVID-19, increased age, male sex, and impaired cognitive and physical function were independently associated with mortality. Understanding these risk factors can aid in the development of clinical prediction models of mortality in this population.

Figure 1.. Receiver Operating Characteristic (ROC) Curves for 30-Day All-Cause Mortality Based on 5 Different Models

The base mode consists of established risk factors (ie, age, sex, race/ethnicity, and comorbidities). ADL indicates activities of daily living; and CFS, Cognitive Function Scale.

Figure 2.. Stratification of 30-Day All-Cause Mortality

The gradient of risk increases as a resident moves from higher quartiles of estimated risk. The box plot lines correspond from bottom of box to top: 25th percentile, median percentile, 75th percentile. The diamond indicates the mean. The whiskers extend to the minimum (25th percentile − 1.5 × interquartile range) and maximum (75th percentile + 1.5 × interquartile range) values. The dots indicate outliers.

Figure 3.. Cumulative Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Mortality Rates

A, Age groups. B, Categories of physical functioning. C, Categories of cognitive functioning. Physical functioning was assessed with the activities of daily living (ADL) score, which ranges from 0 to 28 and describes a patient’s range of impairment from substantial to very severe, with higher values indicating greater impairment. To facilitate interpretation of findings, scores were divided into 4 quartiles (ie, 0-14, 15-19, 20-21, and 22-28). Cognitive functioning was assessed with the Cognitive Function Scale (CFS), which is a hierarchical 4-level scale derived from a resident’s Brief Interview for Mental Status (BIMS) assessment and/or Cognitive Performance Scale (CPS) and integrates their findings into a single score. Accordingly, a residents’ cognitive function is assessed as severely impaired (ie, individuals who were not able to complete the BIMS by themselves or have a CPS score of 5 or 6), moderately impaired (ie, a BIMS score of ≤7 or a CPS score of 3-4), mildly impaired (ie, a BIMS score of 8-12 or a CPS score of ≤2), or cognitively intact (ie, individuals who were able to complete the BIMS and scored between 13 and 15).