Psychometric Validation of the Macedonian-Language Version of the Ultrashort Five-Item Oral Health Impact Profile in the North Macedonian Population (OHIP5-MAC)

<i>Background and Objectives</i>: Due to a lack of an ultrashort questionnaire for Oral Health-Related Quality of Life (OHRQoL) assessment in the North Macedonian population, the OHIP5 was translated into Macedonian language with aim to test its psychometrical properties. <i>Materials and Methods</i>: Two types of reliability were tested: internal consistency by calculating Cronbach's alpha coefficient (general population), and test-retest reliability by calculating intraclass correlation coefficients (ICC) in a convenient sample of dental students who answered the same questions twice. Two types of validity were also tested: convergent validity (via a Spearman rank correlation) and known-group validity (via a Mann-Whitney U test). Responsiveness was tested by calculating the significance of the differences between the pre-treatment and after-treatment scores and by calculating the effect sizes of different dental treatments. <i>Results</i>: The Cronbach alpha coefficient of 0.756 and inter-item correlations above 0.2 pointed out good internal consistency. The test-retest reliability was confirmed by high ICCs and no significant differences between the OHIP5-MAC scores in a period of two weeks as dental students had no oral health changes. The Spearman rank correlation of -0.88 (<i>p</i> < 0.01) between the OHIP5-MAC summary scores and one simple question scoring self-perceived oral health (1-5; 1-worst oral health; 5-excellent oral health) confirmed the convergent validity. Significant differences between subjects with natural teeth and those with removable dentures (<i>p</i> < 0.01) confirmed the know-group validity, as it was predicted that removable denture wearers would have more impairment of oral health than individuals with natural teeth. The sensitivity of a questionnaire to measure changes elicited by dental treatments, i.e., responsiveness, was confirmed in individuals who received different dental treatments and scored significantly better (lower scores) their OHRQoL one month after the treatment, compared to their pretreatment scores (<i>p</i> < 0.05). <i>Conclusions</i>: Generally good psychometric properties of the OHIP5-MAC justify the recommendation for its future use in clinical settings and research.