Preserved Ratio Impaired Spirometry and Risks of Macrovascular, Microvascular Complications and Mortality Among Individuals With Type 2 Diabetes

Abstract

Background: The prospective associations of preserved ratio impaired spirometry (PRISm) with new-onset macrovascular and microvascular complications and mortality among individuals with type 2 diabetes (T2D) and whether PRISm enhances the prediction ability of an established office-based risk score remain to be elucidated.

Research question: Can PRISm be used as a predictor of poor prognosis in individuals with T2D?

Study design and methods: We included 20,047 study participants with T2D and complete data on spirometry at recruitment from the UK Biobank cohort. Multivariable Cox proportional hazards models were used to assess the associations of baseline PRISm (FEV₁ to FVC ratio, ≥ 0.70; FEV₁, < 80% predicted) with subsequent risks of incident stroke (any type), ischemic stroke, myocardial infarction, unstable angina, coronary heart disease, diabetic retinopathy, diabetic kidney disease, all-cause mortality, cardiovascular mortality, and respiratory mortality.

Results: For this cohort analysis, 4,521 patients (22.55% of participants with T2D) showed comorbid PRISm at baseline. Over a median follow-up of 11.52 to 11.87 years, patients with T2D with PRISm at baseline showed higher risks than those with normal spirometry findings of various T2D complications developing and mortality; the adjusted hazard ratios for PRISm were 1.413 (95% CI, 1.187-1.681) for stroke (any type), 1.382 (95% CI, 1.129-1.690) for ischemic stroke, 1.253 (95% CI, 1.045-1.503) for myocardial infarction, 1.206 (95% CI, 1.086-1.339) for coronary heart disease, 1.311 (95% CI, 1.141-1.506) for diabetic retinopathy, 1.384 (95% CI, 1.190-1.610) for diabetic kidney disease, 1.337 (95% CI, 1.213-1.474) for all-cause mortality, 1.597 (95% CI, 1.296-1.967) for cardiovascular mortality, and 1.559 (95% CI, 1.189-2.044) for respiratory mortality, respectively. The addition of PRISm significantly improved the reclassification ability, based on the net reclassification index, of an office-based risk score by 15.53% (95% CI, 10.14%-19.63%) to 33.60% (95% CI, 20.90%-45.79%).

Interpretation: Individuals with T2D with comorbid PRISm, accounting for a considerable proportion of the population with T2D, showed significantly increased risks of adverse macrovascular and microvascular complications and mortality.

Keywords: diabetic complication; office-based risk score; preserved ratio impaired spirometry; type 2 diabetes.