Objective: To evaluate psychometric properties of the Argentine-Spanish SF-36 and to validate the physical component summary (PCS) and mental component summary (MCS) measures.
Study design and setting: A self-administration of the SF-36 with 1-year follow-up was performed in a University-based ambulatory center in Buenos Aires. Diagnoses were abstracted from the chart. Univariate analysis, psychometric methods, and confirmatory factor analyses were conducted.
Results: Of 3,290 subjects, 2,638 had computable scores and were included: 1,938 at their initial contact and 700 from a random sample of other enrollees. Cronbach's alpha ranged from 0.79 to 0.92 in all subscales except for General Health. Age was related to PCS scores (lower in the elderly) but not to MCS scores. PCS and MCS provided good discrimination among mutually exclusive disease categories; minor medical (52.2 vs. 51.1), psychosocial (48.1 vs. 43.0), chronic medical (46.2 vs. 51.0) and both chronic and mental conditions (44.9 vs. 45.1) in PCS and MCS, respectively (P<0.01). Mean annual doctor visits increased from 3.6 to 5.3 in subjects with PCS>55 and PCS<35, and from 4.4 to 6.0 in subjects with MCS>55 and MCS<35, respectively (P<0.0001).
Conclusions: SF-36 is a valid tool for outcome research in Argentina although normative general population studies are needed.