PURPOSE: Pulmonary Function Tests (PFT) are frequently employed for diagnostic purposes; assessment of disability; and surveillance for occupational disability. Although PFTs are used in many different populations, results are effort dependent and may be affected by inadequate effort. There is little information regarding PFT in incarcerated patients (ICPs). There are multiple motivations for ICPs to perform less than optimally on PFT. The purpose of this study is to determine the prevalence of inadequate-patient-effort in PFT of ICPs.
METHODS: A case control study was done in the pulmonology department at The Mount Vernon Hospital (TMVH). 156 ICPs (134 males, 22 females, mean age: 47.3 years-old, mean weight 86.3Kg) who had a PFT evaluation at TMVH between 2002 to 2005 were enrolled. Controls were matched, unincarcerated patients (males: 132, females 24, mean age: 47.3, mean weight: 89.2Kg). All PFT were administered by one of two respiratory therapists and interpreted by one pulmonologist (ZC). Patient effort was determined by direct observation; pattern of the PFT results; and reproducibility of flow volume loops.
RESULTS: The spirometry results for ICP cases and controls (Pre Bronchodilator/post Bronchodilator (% predicted) were:FVC 74.2/78.6 and 71.6/77.2; FEV1: 66.0/69.3 and 69.3/68.9; FEV1/ FVC 71.1/71.2 and 75.9/74.7. Among ICPs 86.5% had an abnormal PFT compared with 70.5% of controls (P<0.05). Among the abnormal PFTs, the majority were obstructive in both groups (obstructive 66.7% vs. 48.6%, restrictive: 20% vs. 20.9% and mixed pattern 13.3vs. 22.4%). ICPs showed significantly higher rates of inadequate effort compared to controls: 26.9% vs. 4.1% (P<0.001). 31% of the abnormal PFT in ICPs were associated to inadequate effort compared to 4% in controls (p<0.001).
CONCLUSION: The prevalence of inadequate-patient-effort on PFTs in ICPs is higher than in unincarcerated controls.
CLINICAL IMPLICATIONS: The pattern of inadequate-patient-effort may have clinical ramifications in incarcerated populations. Where applicable, abnormal testing in ICPs should take into account the possibility of inadequate-poor-effort. Further studies are warranted.
DISCLOSURE: Pavan Kumar Gona, None.