Introduction: Sleep health is essential to overall physical, mental and neurobehavioral well-being. Poor sleep quality has been linked to numerous health conditions, impaired school and work performance and increased risk for accidents. Hence, evaluation of a person's sleep health is vital to any medical examination. Questionnaires such as Pittsburgh Sleep Quality Index (PSQI) have an important role in the preliminary evaluation of sleep health. PSQI has been regarded as the standard instrument to measure sleep quality. It has been translated into several languages and has been validated in various populations. This study aimed to assess the validity and reliability of the Filipino version of the PSQI.

Methods: The Filipino version of the PSQI was administered to 200 adult subjects. After 24-48 hours, the English version of the PSQI was administered to the same respondents. Basic demographic information, co-morbidities and use of medications were obtained. Cronbach's alpha and Kappa test of agreement were measured to test the reliability of the Filipino version while confirmatory factor analysis was used to determine the validity of the translated tool.

Results: The Filipino version of the PSQI was reliable with Cronbach's alpha of 0.70. The agreement coefficient of all items in the questionnaire were all above 0.81 indicating a very good level of agreement between the English and Filipino versions. Confirmatory factor analysis showed that items Q1, Q3, Q4, Q5a-Q5i, Q6, Q7, Q8 and Q9 were significant with p-values below 0.05. Overall, as measured by the Goodness of fit, it showed that the items in the Filipino version of the questionnaire are directly correlated with English PSQI Score.

Conclusion: The Filipino version of the PSQI is a valid and reliable instrument to assess sleep quality.