SARS-CoV-2 and Wisconsin Nursing Homes: Temporal dynamics during the COVID-19 pandemic

Gmehlin, Cameron G.; Rivera, Frida; Ramos-Castaneda, Jorge A.; Pezzin, Liliana E.; Ehn, Diane; Duthie, Edmund H.; Munoz-Price, L. Silvia

Objectives Evidence suggests that quality, location, and staffing levels may be associated with COVID-19 incidence in nursing homes. However, it is unknown if these relationships remain constant over time. We describe incidence rates of COVID-19 across Wisconsin nursing homes while examining factors associated with their trajectory during five months of the pandemic. Design Retrospective cohort study. Setting/Participants Wisconsin nursing homes. Methods Publicly available data from June 1, 2020 to October 31, 2020 were obtained. These included facility size, staffing, Five-star Medicare rating score and components. Nursing home characteristics were compared using Pearson Chi-square and Kruskal-Wallis tests. Multiple linear regressions were used to evaluate the effect of rurality on COVID-19. Results There were a total of 2,459 COVID-19 cases across 246 Wisconsin nursing homes. Number of beds (P<0.001), average count of residents per day (p<0.001) and governmental ownership (p=0.014) were associated with a higher number of COVID-19 cases. Temporal analysis showed that the highest incidence rates of COVID-19 were observed in October 2020 (30.33 cases per 10,000 nursing home occupied-bed days, respectively). Urban nursing homes experienced higher incidence rates until September 2020; then incidence rates among rural nursing homes surged. In the first half of the study period, nursing homes with lower quality scores (1-3 stars) had higher COVID-19 incidence rates. However, since August 2020, incidence was highest among nursing homes with higher quality scores (4-5 stars). Multivariate analysis indicated that over time rural location was associated with increased incidence of COVID-19 (β=0.05, p=0.03). Conclusions and Implications Higher COVID-19 incidence rates were first observed in large, urban nursing homes with low quality rating. By October 2020, the disease had spread to rural and smaller nursing homes and those with higher quality ratings, suggesting that community transmission of SARS-CoV-2 may have propelled its spread.