Association Of Highly Sensitive CRP And COPD Assessment Test (CAT) Scores With Clinical Outcomes In Stable COPD Patients

Abstract

Introduction: Chronic obstructive pulmonary disease (COPD) is a progressive inflammatory lung disorder associated with systemic inflammation, exacerbation, and increased morbidity. In addition to pulmonary dysfunction, COPD is influenced by systemic factors, including comorbidities such as cardiovascular disease, diabetes mellitus, and hypertension. Hs-CRP is a marker of systemic inflammation linked to COPD activity and prognosis, whereas the COPD assessment test (CAT) score quantifies symptom burden and its impact on daily life and health status.

Aim: To study the association between hs-CRP levels and CAT scores and clinical outcomes in patients with stable COPD.

Materials and Methods: This prospective observational study included 70 patients with stable COPD aged ≥30 years at SRM Hospital over six months. Demographic data, smoking history, pulmonary function test results, hs-CRP levels, and CAT scores were obtained. Statistical analyses included Pearson and Spearman correlation coefficients, chi-square tests, and logistic regression to assess the association between hs-CRP levels, CAT scores, and clinical outcomes.

Results: The mean age of the patients was 55.8 ± 8.6 years, with male predominance (81.4%). A significant positive correlation was observed between hs-CRP levels and CAT scores (r = 0.448, p < 0.0001). Most patients were of normal weight (41.4%) or overweight (40%), and 40% were smokers. Diabetes mellitus and hypertension were present in 34.3% and 27.1% of the patients, respectively. A significant moderate positive correlation was found between the hs-CRP levels and CAT scores (r = 0.448, p < 0.0001). Patients with very high CAT impact scores had the highest hs-CRP levels (9.10 ± 2.24 mg/L), whereas those with low impact scores had the lowest (5.69 ± 0.85 mg/L). Exacerbation frequency over six months showed a strong positive correlation with hs-CRP levels (Spearman’s rho = 0.847, p < 0.0001). Logistic regression analysis identified hs-CRP as a significant predictor of clinical outcomes (OR = 75.147, p = 0.004), whereas CAT scores were not (p = 0.568).

Conclusion: Elevated hs-CRP levels correlate with increased exacerbation frequency, suggesting its potential as a prognostic biomarker in stable COPD. Although CAT scores reflect the symptom burden, they may not independently predict clinical outcomes. Including hs-CRP in COPD assessment may enhance risk stratification and guide personalised management strategies