# Risk factors for COPD exacerbations and mortality, and variation between primary care settings: the PRAXIS cohort study in Sweden

## TL;DR

The study found that COPD exacerbations and mortality are more influenced by individual patient factors than differences between primary care centers in Sweden.

## Contribution

The study identifies anxiety and cardiovascular disease as significant risk factors for COPD mortality and highlights the importance of individualized care.

## Key findings

- Variability between primary care centers had minimal impact on COPD outcomes.
- Anxiety and cardiovascular disease were strongly associated with increased mortality risk.
- Body mass index showed a U-shaped relationship with mortality.

## Abstract

We aimed to examine the variability of chronic obstructive pulmonary disease (COPD) exacerbations and mortality, between primary healthcare centres, and their associations with comorbid diseases and body mass index, during an 8-year follow-up.

This was a cohort study using multilevel modelling with follow-up from 2014 to 2022. Data came from questionnaires in 2014 and 2022 and medical record reviews between 2004 and 2014. The main outcomes were exacerbations in 2022 and mortality by 2022. Exacerbations were defined as any emergency visit, and/or use of oral steroids or antibiotics due to worsening of COPD symptoms during the previous 6 months.

The PRAXIS study included patients at 76 primary healthcare centres in central Sweden.

Primary care patients aged ≤75 years and with a diagnosis of COPD in their medical records between 2007 and 2010 were included in 2014 (n=1163) and followed up in 2022 (n=906). There were no other exclusion criteria.

The 809 patients with complete data attended 70 primary care centres. Multilevel multinomial regression estimated risks of exacerbations and mortality, calculating relative risk ratios (RRRs) with 95% CIs. The intraclass correlation coefficient (ICC) quantified the proportion of variance attributed to variability between centres. The ICC was 0.024, indicating 2.4% of the variation was explained by differences between centres. Patients with a history of depression in 2014 had an increased risk of subsequent exacerbations (RRR 1.95, 95% CI 1.13 to 3.39). For mortality, there were associations with history of anxiety, RRR 3.71 (95% CI 2.06 to 6.87), or cardiovascular disease, especially chronic heart failure, RRR 2.69 (95% CI 1.36 to 5.33). Body mass index had a U-shaped association with mortality.

The variability between centres was small and patient factors appear to be of more importance for COPD exacerbations and mortality than differences between these primary care settings. As expected, pre-existing cardiovascular disease is associated with future excess mortality risk, but, notably, anxiety may also be an important risk factor. Individualised care and management of comorbidity is thus essential among patients in primary care with COPD.