Frailty is a common geriatric syndrome associated with falls, disability, hospitalization, and mortality. Primary care screening tools must be simple, time-efficient, and accurate. This study aimed to develop and validate the Frailty Questionnaire-5 (FQ-5), adapted from the PRISMA-7, for frailty screening in a primary care setting. We conducted a cross-sectional study of 328 ambulatory, community-dwelling older adults (age 60–91 years; 84 males, 244 females) recruited via consecutive sampling in suburban Northeast Thailand. Following linguistic validation of PRISMA-7, the FQ-5 was developed by removing two low-performing items and adjusting the age threshold. Criterion validity and clinical association were assessed against the modified Thai Frailty Index (mTFI). Internal consistency and 7–14-day test–retest reliability (n = 33) were also evaluated. Frailty prevalence was 29.9% (n = 98) according to the mTFI and 24.1% (n = 79) based on the Thai PRISMA-7 (cutoff ≥ 3). For the FQ-5, prevalence varied by threshold: 53.7% (n = 176) at cutoff ≥ 1 and 24.7% (n = 81) at cutoff ≥ 2. The FQ-5 demonstrated good discrimination (AUC = 0.81; 95% CI: 0.76–0.86). A cutoff ≥ 2 achieved the highest overall classification accuracy (80.8%), with sensitivity 59.2% and specificity 90.0% (dOR = 13.05). Meanwhile, a cutoff ≥ 1 maximized sensitivity (84.7%) at the expense of specificity (59.6%). The FQ-5 was significantly associated with adverse outcomes, including ADL dependency and falls. Test–retest reliability was excellent (ICC = 0.86) and precision (SEM = 0.42, MDC = 1.17), with no significant systematic bias (mean difference = -0.12). The FQ-5 is a brief, reliable, and clinically relevant frailty screening tool for Thai primary care, with potential for adaptation in countries with similar healthcare and demographic profiles. In practice, FQ-5 ≥ 2 is suitable for rule-in screening in primary care, whereas ≥ 1 supports early case-finding to prompt full frailty assessment. Thai Clinical Trials Registry (TCTR), TCTR20250818010; registered 18 August 2025 (retrospectively registered).
Damrongtawat et al. (Wed,) studied this question.