Restrictive spirometric pattern and true pulmonary restriction in a general population sample aged 50 - 64 years

Area of Science:

• Pulmonary Medicine
• Diagnostic Accuracy
• Epidemiology

Background:

• The diagnostic accuracy of the proxy restrictive spirometric pattern (RSP) for identifying true pulmonary restriction is often low.
• Existing data primarily comes from referred patients, lacking general population insights.
• This study investigates RSP's validity as a proxy for true pulmonary restriction in a general population cohort.

Purpose of the Study:

• To validate the proxy restrictive spirometric pattern (RSP) against true pulmonary restriction in a general population.
• To assess the diagnostic accuracy of RSP using spirometry and total lung capacity measurements.

Main Methods:

• Utilized data from the Swedish CArdioPulmonary bioImage Study (SCAPIS Pilot) with 983 adults aged 50-64.
• Defined true pulmonary restriction as TLC < LLN (Z score < -1.645) and RSP as FEV1/FVC ≥ LLN and FVC < LLN post-bronchodilation.
• Calculated sensitivity, specificity, and likelihood ratios with 95% confidence intervals.

Main Results:

• Prevalence of true pulmonary restriction was 5.4%, while RSP prevalence was 3.4%.
• RSP demonstrated a sensitivity of 0.34 (0.20-0.46) and a specificity of 0.98 (0.97-0.99).
• Positive likelihood ratio was 21.1 (11.3-39.4), and negative likelihood ratio was 0.67 (0.55-0.81).

Conclusions:

• The proxy restrictive spirometric pattern (RSP) exhibits low accuracy in diagnosing true pulmonary restriction.
• Findings support previous research indicating RSP's utility in excluding pulmonary restriction.
• RSP may be a valuable tool for ruling out, but not confirming, pulmonary restriction in population studies.