External validation of the hospital frailty risk score among hospitalised home care clients in Canada: a retrospective cohort study.

BACKGROUND: The Hospital Frailty Risk Score (HFRS) is scored using ICD-10 diagnostic codes in administrative hospital records. Home care clients in Canada are routinely assessed with Resident Assessment Instrument-Home Care (RAI-HC) which can calculate the Clinical Frailty Scale (CFS) and the Frailty Index (FI). OBJECTIVE: Measure the correlation between the HFRS, CFS and FI and compare prognostic utility for frailty-related outcomes. DESIGN: Retrospective cohort study. SETTING: Alberta, British Columbia and Ontario, Canada. SUBJECTS: Home care clients aged 65+ admitted to hospital within 180 days (median 65 days) of a RAI-HC assessment (n = 167,316). METHODS: Correlation between the HFRS, CFS and FI was measured using the Spearman correlation coefficient. Prognostic utility of each measure was assessed by comparing measures of association, discrimination and calibration for mortality (30 days), prolonged hospital stay (10+ days), unplanned hospital readmission (30 days) and long-term care admission (1 year). RESULTS: The HFRS was weakly correlated with the FI (ρ 0.21) and CFS (ρ 0.28). Unlike the FI and CFS, the HFRS was unable to discriminate for 30-day mortality (area under the receiver operator characteristic curve (AUC) 0.506; confidence interval (CI) 0.502-0.511). It was the only measure that could discriminate for prolonged hospital stay (AUC 0.666; CI 0.661-0.673). The HFRS operated like the FI and CFI when predicting unplanned readmission (AUC 0.530 CI 0.526-0.536) and long-term care admission (AUC 0.600; CI 0.593-0.606). CONCLUSIONS: The HFRS identifies a different subset of older adult home care clients as frail than the CFS and FI. It has prognostic utility for several frailty-related outcomes in this population, except short-term mortality.

Protective effects of prior third dose mRNA vaccination in rural nursing home residents during SARS-CoV-2 outbreaks.

BACKGROUND: In Canada, mortality due to SARS-CoV-2 disproportionately impacted residents of nursing homes (NH). In November 2021, NH residents in the Canadian province of Manitoba became eligible to receive three doses of mRNA vaccine but coverage with three doses has not been universal. The objective of this study was to compare the protection from infection conferred by one, two, and three doses of COVID-19 mRNA vaccine compared to no vaccination among residents of nursing homes experiencing SARS-CoV-2 outbreaks. METHODS: Infection Prevention and Control reports from 8 rural nursing homes experiencing outbreaks of SARS-CoV-2 between January 6, 2022, and March 5, 2022, were analyzed. Attack rates and the number needed to vaccinate (NNV) were calculated. RESULTS: SARS-CoV-2 attack rate was 65% among NH residents not vaccinated, 58% among residents who received 1-2 doses of mRNA COVID-19 vaccine, and 28% among residents who had received 3 vaccine doses. The NNV to prevent one nursing home resident from SARS-CoV-2 infection during an outbreak was 3 for a vaccination with 3 doses and 14 for 1-2 doses of COVID-19 mRNA vaccine. The superiority of receiving the third dose was statistically significant compared to 1-2 doses (Chi-Squared, p < 0.00001). CONCLUSIONS: Nursing home residents who received three doses of COVID-19 mRNA vaccine were at lower risk of SARS-CoV-2 infection compared to those who received 1-2 doses. Our analyses lend support to the protective effects of the third dose of mRNA vaccine for NH residents in the event of a SARS-CoV-2 outbreak.