Abstract
Background Evidence on risk factors for a complicated course of lower respiratory tract infections (LRTIs) in primary care remains limited and often consensus based. While socioeconomic status (SES) and migration background have been linked to complicated LRTIs in population-based studies, their predictive value in primary care remains unclear. Consequently, these factors are not incorporated within current guidelines, which may contribute to health inequalities. Therefore, we aimed to evaluate the added value of SES and migration background as predictive factors of a complicated course of LRTIs in primary care. Methods Routine care data from Dutch general practices participating in the Extramural LUMC Academic Network database (Leiden-The Hague-Zoetermeer region) from 2014 to 2023, excluding COVID-19 years, was linked to sociodemographic and hospital claims data from Statistic Netherlands. Adults presenting with LRTI complaints were included (n = 145,445). Multivariable logistic regression models were constructed to predict 30-day hospitalisation or death following LRTI. Models included conventional risk factors with SES and migration background subsequently added. Results In this study we show that after adjusting for conventional clinical factors, SES is a strong predictor of a complicated course of LRTI, whereas migration background is not. Patients in the lowest SES category have an adjusted odds ratio of 1.46 (95%CI: 1.31 – 1.62) for a complicated course compared to the highest. Conclusions SES is a strong predictor of a complicated course of LRTI in primary care, even after adjusting for conventional risk factors. The incorporation of SES into clinical decision tools and guidelines has the potential to enhance risk-stratification of patients with LRTI in daily practice of primary care, thereby supporting more equitable care. Lower respiratory tract infections (LRTIs) (infectious bronchitis, bronchiolitis, and pneumonia) represent the leading cause of infectious disease burden in Europe, including the Netherlands1,2. LRTIs can result in severe complications, such as respiratory failure and death, either directly or through related health consequences. Seasonal peaks in LRTI incidence during winter months place substantial strain on healthcare systems, a challenge that is expected to intensify due to an ageing population and the risk of emerging pandemics3,4. The Dutch healthcare system is characterised by universal coverage andbroadaccesstoprimary,hospital,andspecialistcare,rankingamongthe 1Department of Public Health and Primary Care, Health Campus The Hague, Leiden University Medical Center, Leiden, The Netherlands. 2Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands. 3Infectious Disease Control, Academic Collaborative Centre for Public Health Lumens, The Hague and Leiden, the Netherlands. 4Infectious Disease Control, Public Health Service Haaglanden, The Hague, The Netherlands. 5LUCID, Subdepa