Validating the questionnaire for verifying stroke-free status (QVSFS) by neurological history and examination

Background and Purpose-The Questionnaire for Verifying Stroke-Free Status ( QVSFS) is an 8-item structured interview designed to identify stroke-free i ndividuals. Previously, the QVSFS was validated with medical record review in a cohort with a low prevalence (7.1%) of stroke or transient ischemic at tack (TIA). The objective of this study was to evaluate the validity of the QVSFS by comparing it with stroke status as determined by neurological his tory and examination in a population with a higher prevalence of stroke. Methods-A research assistant administered the QVSFS to outpatients from Vet erans Administration stroke and general medicine clinics. Subjects were def ined as QVSFS negative if responses to all 8 questions were negative. Quest ions requiring rephrasing or clarification were noted. Neurologists, blinde d to QVSFS scores, interviewed and examined all subjects to determine strok e-free status, defined as no history or examination findings of previous st roke and/or TIA. Results-One hundred fifty-five subjects were examined; mean age was 70 year s; 98.1% were male. Seventy-eight subjects were determined to be stroke fre e by the neurologist. The negative predictive value of the QVSFS was 0.96, with positive predictive value of 0.71. No question required rephrasing or clarification >5 times. Twenty-two subjects (14.2%) required rephrasing or clarification of at least 1 question. Conclusions-The QVSFS can effectively identify stroke-free individuals with a high degree of accuracy, even in a population with a large proportion of patients with prior stroke or TIA. Accuracy for identifying subjects with stroke and/or TIA is lower, but the QVSFS may still be useful as a screenin g tool in that regard.