RESUMEN
SUMMARY OBJECTIVE: To determine the cutoff point of the Clinical-Functional Vulnerability Index-20 to detect poor quality of life in the elderly in Primary Health Care. METHODS: This cross-sectional study was carried out in Primary Health Care units of Ceilândia (DF, Brasil) between September 2019 and January 2020. Four hundred and fifty-eight individuals were included in the study and answered the Clinical-Functional Vulnerability Index-20 (IVCF-20) and the World Health Organization Quality of Life - WHOQOL-BREF (validated to access quality of life) instruments. Based on the WHOQOL-BREF answers, three subgroups were created: poor, good and undetermined quality of life. The receiver operating characteristic curve (using Youden index) showed the IVCF-20 cutoff point to detect poor quality of life (in individuals with good quality of life as the Control Group), and therefore diagnostic tests were performed. RESULTS: The IVCF-20 cutoff point to detect poor quality of life was ≥11. The area under the receiver operating characteristic curve was 0.97 (95%CI 0.95-0.98). The IVCF-20 diagnostic tests showed good sensitivity (88.1%) and specificity (84.9%). CONCLUSIONS: The IVCF-20 ≥11 detected poor quality of life adequately in the elderly in Primary Health Care. These data suggest that elderly individuals with IVCF ≥11 should attend appointments more often in Primary Health Care or geriatrics collaborative care, considering the impact that quality of life can have on the elderly population's mortality.