BackgroundHypothyroidism is often diagnosed, and subsequently treated, due to health-related quality of life (HRQL) issues. However, HRQL following treatment has never previously been assessed in longitudinal descriptive studies using validated instruments.ObjectiveTo investigate disease-specific (ThyPRO) and generic (SF-36) HRQL, following levothyroxine therapy in patients with hypothyroidism due to autoimmune thyroiditis.MethodsThis prospective cohort study was set at endocrine outpatient clinics at two Danish university hospitals. Seventy-eight consecutive patients were enrolled and completed HRQL questionnaires before, six weeks, and six months after initiation of levothyroxine therapy. Normative ThyPRO (n = 739) and SF-36 (n = 6,638) data were available for comparison and changes in HRQL following treatment were estimated and quantified.ResultsPrior to treatment, all ThyPRO scales were significantly impacted (p<0.0001), compared to the general population sample. The same was observed for seven of eight SF-36 scales, the exception being Bodily Pain. Tiredness (ThyPRO) and Vitality (SF-36) were the most markedly impacted scales. After six weeks of treatment, nine of thirteen ThyPRO scales had significantly improved. ThyPRO improvements were consistent at six months, where five of eight SF-36 scales had also significantly improved, but deficits persisted for a subset of both ThyPRO and SF-36 scales.ConclusionsIn this population of hypothyroid patients, HRQL was widely affected before treatment, with tiredness as the cardinal impairment according to both ThyPRO and SF-36. Many aspects of HRQL improved during the first six months of LT4 therapy, but full recovery was not obtained. Our results may help clinicians inform patients about expected clinical treatment effects.

The ThyPRO was responsive to treatment across the range of benign thyroid diseases. We suggest implementing this measurement instrument as a patient-reported outcome in clinical studies and in clinical management.

A 39-item version of the ThyPRO, with good measurement properties, was developed and is recommended for clinical use.