Validity and Reliability of the SF-36 Administered to Caregivers of Patients with Alzheimer’s Disease: Evidence from a South American Sample

Abstract

Background: Being a caregiver of a patient with Alzheimer’s disease is associated with impaired health status and declines in health-related quality of life (HRQoL). This paper evaluates the reliability and validity of the Argentinean version of the Medical Outcomes Study Short-Form Health Survey (SF-36) among caregivers of patients with Alzheimer’s disease. Methods: Forty-eight caregivers of Alzheimer’s disease patients completed the SF-36, the Zarit Burden Interview (ZBI) and the Neuropsychiatric Inventory (NPI). Patients were evaluated for dementia severity using the Clinical Dementia Rating (CDR) and for cognitive status using the Mini Mental State Examination (MMSE). Results: The SF-36 scales demonstrated adequate-to-strong internal consistency (Cronbach’s alpha range: 0.72 to 0.92). Correlations between the SF-36 scales and the ZBI were moderate to strong (range: –0.19 to –0.79, all p < 0.01 expect for physical function). Significant correlations between the SF-36 scales and the CDR, MMSE and NPI were lower (range: –0.30 to –0.40, p < 0.001) and strongest in mental health-related scales of the SF-36. The SF-36 demonstrated good factorial validity. Conclusions: The Argentinean translation of the SF-36 is reliable and valid for use to measure the HRQoL of caregivers of patients with Alzheimer’s disease.