Psychometric properties of the national eye institute refractive error correction quality-of-life questionnaire among Iranian patients

To evaluate the psychometric properties of the national Eye Institute refractive error correction quality of life questionnaire [NEI-RQL-42] among Iranian patients with refractive errors. Two samples of patients [n1 = 296, n2 = 95] were consecutively selected from the eye clinic of the Boo-Ali Hospital, Qazvin. A forward-backward procedure was conducted to translate and cross-culturally adapt the Iranian version of the NEI-RQL-42. A homogeneity, stability, and reliability test was conducted for the first sample after a two-week interval. Convergent validity was computed using the correlation between the NEI-RQL-42 subscale scores, National Eye Institute-Visual Functioning Questionnaire [NEI-VFQ-25], and the Short Form-36 [SF-36]. Furthermore, Known-group analysis was performed, to determine the discriminant validity between the subgroups of patients with hyperopia, emmetropia, and myopia. Responsiveness to clinical change was tested by administering NEI-RQL-42 on the second sample that was scheduled for surgery. Homogeneity was satisfactory with the Cronbach's alpha coefficients ranging between 0.70 and 0.92. The 13 subscales of the NEI-RQL-42 showed a considerable stability in intra-class-correlation [ICC] ranging between 0.70 and 0.89. Positive correlation coefficients were found among all subscales of the NEI-RQL-42 and the other quality-of-life instruments [NEI-VFQ-25 and SF-36]. The NEI-VFQ-25 displayed excellent discriminant validity to differentiate the subgroups of patients, and was found to be responsive to change after the surgical correction at three months. The Iranian version of the NEI-RQL-42 is a valid and reliable instrument to assess refractive error correction quality-of-life in Iranian patients. Moreover this questionnaire can be used to evaluate the effectiveness of interventions in patients with refractive errors

Validity and reliability of short form-12 questionnaire in Iranian hemodialysis patients

The aim of the study was to assess the validity and reliability of the SF-12 questionnaire in a sample of Iranian patients undergoing hemodialysis. One hundred and forty-four hemodialysis patients were included from dialysis centers in Zanjan, Iran, and were asked to complete the SF-12 and SF-36 questionnaires. An initial test-retest reliability evaluation was performed on a sample of 70 patients from the total group, with a retest interval of 14 days. Reliability was estimated by internal consistency and validity was assessed using known-group comparisons and construct validity on the patient group as a whole. A linear regression analysis was used to assess any variation in the physical component summary and mental component summary scores of the SF-36 with the respective component summary scores of the SF-12. In addition, the factor structure of the questionnaire was extracted by performing a confirmatory factor analysis. Cronbach alpha for physical and mental component summaries were 0.89 and 0.90, respectively. The SF-12 showed a good discriminatory ability between subgroups of patients based on demographic and clinical variables. The confirmatory factor analysis for the original two-factor structure showed a good fit index [chi2=23.30, degrees of freedom=13], goodness-of-fit index=0.96, and root mean squared error of approximation=0.079]. In general, the SF-12 has good psychometric properties and can be used as a shorter version of the SF-36 questionnaire in future studies involving Iranian patients undergoing hemodialysis