Evaluation of incidence and risk profile for suffering Covid-19 infection by underlying conditions among middle-aged and older adults in Tarragona

Abstract

Background: Population-based data on the current Covid-19 pandemic is scarce. This study investigated incidence and risk to suffer Covid-19 by baseline underlying conditions in people ≥50 years in Tarragona region across march-april 2020. Methods: Population-based retrospective cohort study involving 79,071 adults ≥50 years-old in Tarragona region (Southern Catalonia, Spain). Cohort characteristics (age, sex, residence, vaccinations history and comorbidities) were established at baseline, and Covid-19 cases occurring between 01/03/2020-30/04/2020 were registered. Cox regression analysis calculating Hazard ratios (HRs) adjusted by age, sex and comorbidities was used to estimate risk for Covid-19. Results: Across study period, 1,547 cohort members were PCR tested (22.6% positive) and 367 were presump- tive cases without PCR tested. Considering PCR-confirmed Covid-19, incidence (per 100,000 persons-period) was 441 overall (248, 141, 424, 1,303 and 3,135 in 50-59, 60-69, 70- 79, 80-89 and ≥90 years-old, respectively; 380 in men and 497 in women; 259 in community-dwelling and 10,571 in nursing-home). By comorbidities, maximum incidence emerged among persons with neurological disease (2,723), atrial fibrillation (1,348), chronic renal failure (1,050), car- diac disease (856), respiratory disease (798) and diabetes (706). Lower incidence appeared in rheumatic diseases (230) and smokers (180). In multivariable analysis focused on community-dwelling individuals (N=77,671), only cardiac disease (HR: 1.47; 95% CI: 1.01-2.15; p=0.045) and respiratory disease (HR: 1.75; 95% CI: 1.00-3.02; p=0.051) were associated with an increased risk, whereas smoking (HR:0.43; 95% CI: 0.25-0.74; p=0.002) and influenza vaccinated (HR: 0.63; 95% CI: 0.43-0.92; p=0.015) appeared associated with a decreased risk. Conclusions: Apart of increasing age and nursing- home residence, chronic respiratory and cardiac disease appear at increased risk for suffering covid19. This study investigated population-based incidence of Covid-19 infection by underlying conditions among adults ≥50 years in Tarragona (Southern Catalonia, Spain) across two first months pandemic period.