Work

L-Shaped Association of C-Reactive Protein-Albumin-Lymphocyte Index and COPD Incidence: A Nationwide Cohort Study in the UK Biobank

Year: 2026

Type: article

Abstract: Background: The C-reactive protein–albumin–lymphocyte (CALLY) index has shown prognostic value in various chronic conditions, but its prospective association with incident chronic obstructive pulmonary disease (COPD) and potential non-linear dose–response patterns remain unexplored. Methods: This prospective cohort study included 292,945 UK Biobank participants. Multivariable Cox proportional hazards regression was used to estimate the association between the natural-log-transformed CALLY (ln-CALLY) index and incident COPD. Restricted cubic spline (RCS) curves and two-segment Cox regression were applied to characterize non-linear associations and identify inflection points. Subgroup and sensitivity analyses were conducted to assess robustness. Results: During a mean follow-up of 13.6 years, 6618 incident COPD events occurred. Each one-unit increment in ln-CALLY was associated with a 17% lower risk of COPD in the fully adjusted model (HR = 0.83, 95% CI: 0.81– 0.85, P < 0.001). The highest quartile exhibiting a 41% risk reduction versus the lowest (HR = 0.59, 95% CI: 0.54– 0.64, P < 0.001). RCS analysis revealed a significant L-shaped relationship. Threshold effect analysis identified an inflection point at ln-CALLY = 7.00; below this threshold, each one-unit increase was associated with a 19% risk reduction (HR = 0.81, 95% CI: 0.78– 0.83, P < 0.001), whereas above the threshold the association was non-significant. The inverse association was more pronounced in participants aged < 65 years. Sensitivity analyses yielded consistent results. Conclusion: The CALLY index exhibits a significant L-shaped association with incident COPD risk, characterized by a pronounced protective effect below ln-CALLY = 7.00 and a risk plateau above this threshold. These findings support the broader concept that immuno-nutritional status is a determinant of respiratory health. Keywords: C-reactive protein–albumin–lymphocyte index, COPD, immuno-nutritional biomarker, UK biobank, prospective cohort study, threshold effect

Source: International Journal of COPD

DOI: 10.2147/copd.s640670

Authors: Yushan Shi, Huihui Jiang, Shuangshuang Pu, Yaobei Liu, Yan Wang, Weifang Liu

Institutions: Shandong University of Traditional Chinese Medicine, Affiliated Hospital of Shandong University of Traditional Chinese Medicine

Language: English

Topic: Chronic Obstructive Pulmonary Disease (COPD) Research

Subfield: Pulmonary and Respiratory Medicine

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: gold

Estimated APC paid: $2,836