Risk factors for developing symptomatic COVID-19 in older residents of nursing homes: A hypothesis-generating observational study.

Background. COVID-19 pandemic has had a major impact on society, including on residents of nursing homes (NH), who have a higher risk of complications and mortality due their physical and intellectual disabilities. Aim. To identify which risk factors associated with developing COVID-19 infection with symptoms in institutionalized older people. Methods. A 1-year longitudinal multicenter study was conducted in 5 NH during the period December 2019 to March 2021. The inclusion criteria used were residents aged 65 years or over, living in the NH permanently, with a diagnostic test for COVID-19 confirmed by reverse transcription polymerase chain reaction and/or serological test. The main variable was symptomatic COVID-19, with at least one of the following symptoms (fever, respiratory difficulties, cough, diarrhea, sudden urinary incontinence and disorientation or delirium). Three assessments were performed: baseline, six and twelve months follow-up. Descriptive and bivariate analysis (calculating relative risk-RR) were performed, considering a 95% confidence level and a statistically significant p <0.05. Results. Of the total sample of 78 individuals who tested positive for COVID-19, mean age 84.6 years (SD=7.8), 62 (79.5%) were female; 40 (51.3%) participants presented with COVID-19 symptoms. Living in a private NH (RR=3.6, 95% CI [1.2-11.0], p =0.023) and having suffered a stroke (RR=4.1, 95% CI [1.1-14.7], p =0.033) were positively associated with developing COVID-19 infection with symptoms. Conclusions. Having suffered a stroke and living permanently in a private health care facility were positively associated with symptomatic COVID-19 in this sample of institutionalized older people.