Scottish Index of Multiple Deprivation (SIMD) Indicators as Predictors of Mortality Among Patients Hospitalised with COVID-19 Disease in the Lothian Region, Scotland During the First Wave: A Cohort Study

Abstract Background: Sars-CoV-2, the causative agent of COVID-19, has led to more than 100,000 deaths in the UK and multiple risk factors for mortality including age, sex and deprivation have been identified. This study aimed to identify which indicators of Scottish Index of Multiple Deprivation (SIMD), an area-based deprivation index, were predictive of mortality. Methods: This was a prospective cohort study of anonymised electronic health records of 710 consecutive patients hospitalised with Covid-19 disease between March and June 2020 in the Lothian Region of Southeast Scotland. Data sources included automatically extracted data from national electronic platforms and manually extracted data from individual admission records. Exposure variables of interest were SIMD quintiles and more specifically 12 indicators of deprivation deemed clinically relevant selected from the SIMD. Our primary outcome was mortality. Univariable and multivariable logistic regression analyses adjusted for age and sex were used to determine measures of association between exposures of interest and the primary outcome. Results: After adjusting for age and sex, we found an increased risk of mortality in the more deprived SIMD quintiles 1 and 3 (OR 1.75, CI 0.99-3.08, p=0.053 and OR 2.17, CI 1.22-3.86, p=0.009, respectively), but this association was not significant in our multivariable model adjusted for co-morbidities and clinical parameters of severity at admission. Of the 12 pre-selected indicators of deprivation, two were associated with greater mortality in our multivariable analysis: income deprivation rate categorised by quartile (Q4 (most deprived): 2.11 (1.20-3.77) p=0.011)) and greater than expected hospitalisations due to alcohol per SIMD data zone (1.96 (1.28-3.00) p=0.002)). Conclusions: In contrast to other studies, deprivation quintile distribution was not predictive of mortality in our cohort. This possibly reflects the greater affluence and ethnic homogeneity of the Lothian Region compared to the rest of Scotland. We identified an increased risk of mortality in patients residing in areas with greater income-deprivation and/or number of hospitalisations due to alcohol. In areas where aggregate measures fail to capture pockets of deprivation, specific indicators may be helpful in targeting resources to residents at risk of poorer outcomes from Covid-19.