PREVALENCE AND CLINICAL CORRELATES OF PRESERVED RATIO IMPAIRED SPIROMETRY AMONG ADULTS ATTENDING A TERTIARY-CARE NON-COMMUNICABLE DISEASE CLINIC

Abstract

Background: Preserved ratio impaired spirometry (PRISm) is an under-recognized spirometric abnormality that may occur in individuals with cardiometabolic comorbidities despite absence of overt obstructive lung disease. This study aimed to estimate the prevalence of PRISm and evaluate its clinical and spirometric correlates among adults attending a tertiary-care non-communicable disease clinic.

Methods: This prospective observational study included 100 adults aged more than 40 years with at least one non-communicable disease, including diabetes mellitus, hypertension, or dyslipidemia. Demographic, anthropometric, clinical, smoking-related, and dyspnea data were collected. Post-bronchodilator spirometry was performed, and participants were classified as having normal spirometry, obstructive spirometry, or PRISm. PRISm was defined as FEV₁ <80% predicted with FEV₁/FVC ≥0.70. Associations were assessed using chi-square or Fisher’s exact test, and spirometric parameters were compared using one-way ANOVA.

Results: The mean age was 61.95 ± 6.74 years, and 53.0% were men. Normal spirometry was observed in 62.0% of participants, obstructive spirometry in 23.0%, and PRISm in 15.0%. Among PRISm cases, restrictive PRISm was more frequent than non-restrictive PRISm (73.3% vs 26.7%). Lung-function pattern was significantly associated with sex, high waist circumference, diabetes mellitus, hypertension, dyslipidemia, smoking status, number of NCD comorbidities, and mMRC dyspnea grade. Spirometric parameters differed significantly across groups.

Conclusion: PRISm was common among adults attending an NCD clinic and was associated with central obesity, cardiometabolic comorbidity, and dyspnea. Routine spirometry may help identify unrecognized respiratory impairment in high-risk NCD populations.