Background There have been large regional differences in COVID-19 virus activity across the UK with many commentators suggesting that these are related to age, ethnicity and social class. There has also been a focus on cases, hospitalisations and deaths rather than on hospitalisation rates expressed per 100,000 population. The purpose of our study was to examine regional variation in COVID-19 positive hospitalisation rates in Scotland during the first wave of the pandemic and the possibility that these might be related to population density. Methods and findings This was a repeated point prevalence study. The number of COVID-19 positive patients hospitalised in the eleven Scottish mainland health boards peaked at 1517 on 19th April, then fell to a low of 243 on 16th August before rising slightly to 262 on 15th September. In July, August and September only four boards had more than 5 hospitalised patients. There was a statistically significant relationship between hospitalisation rates and population density on 97.7% of individual days during the first wave of the pandemic (Pearson’s r 0.62–0.93, with 123 of a possible 174 days having p values <0.001). Multiple linear regression analyses performed on data from the 11 mainland boards across six time points suggest that population density accounted for 70.2% of the variation in hospitalisation rate in April, 72.3% in May, 81.2% in June, 91.0% in July, 91.0% in August, and 88.1% in September. Neither population median age nor median social deprivation score at health board level were statistically significant in the final model for hospitalisation. Conclusion There were large differences in crude COVID-19 hospitalisation rates across the 11 mainland Scottish health boards, that were significantly related to population density. Given that lockdown was originally introduced to prevent the NHS from being overwhelmed, we believe our results support a regional rather than a national approach to lifting or reimposing more restrictive measures, and that hospitalisation rates should be part of the decision making process.

Background Covid-19 virus activity appears to have affected some parts of the United Kingdom more than others. Dumfries and Galloway (D&G) has seen fewer hospitalised cases than predicted. We wondered whether this might be related at least in part to population density. Methods We compared Covid-19 hospitalisation rates/100,000 population in D&G with those of the other 10 mainland Scottish health boards. We chose two time points: 19th April which was the peak of the pandemic in Scotland and 15th May, seven and a half weeks after lockdown. We used chi square and odds ratios with 95% confidence intervals to test for differences in hospitalisation rates and Pearson correlation coefficient to examine the relation between hospitalisation rates and population density. Population density for each health board was provided by National Records of Scotland. Results Hospitalisation in D&G was 13.4/100,000 on 19th April, falling to 1.3/100,000 by 15th May. Corresponding hospitalisation rates in Greater Glasgow & Clyde (GGC) were 50.1/100,000 and 38.9/100,000. Compared to GGC, hospitalisation rates in D&G were 3 times lower at peak (OR 0.27, 95% CI 0.17, 0.42) and 30 times lower by 15th May (OR 0.03, 95% CI 0.01, 0.14). Hospitalisation rates for the other health boards lay in between values recorded for D&G and GGC and fell in 10 of the 11 boards between these two dates. There was a positive association between hospitalisation rate and population density (r=0.756, p=0.007 on 19th April and r=0.840, p<0.001 for 15th May). Conclusion We have confirmed there are large differences in Covid-19 hospitalisation rates across the 11 mainland Scottish health boards, that are in part related to population density. These data support a regional rather than one nation approach to easing Covid-19 restrictions.