Purpose: Studies of desmopressin in children with primary nocturnal enuresis show a greater than 90% decrease in wet nights in 20% to 30%, a 50% to less than 90% decrease in 20% to 40% and less than a 50% decrease in up to 60%. Insufficient response to desmopressin is attributable to various factors, including differences in the primary nocturnal enuresis definition, underlying bladder dysfunction and/or desmopressin pharmacokinetic characteristics. However, little attention has been given to poor compliance with therapy as a possible explanatory factor. For a drug with an effect duration limited to the night after administration a high degree of compliance is essential to ensure consistent therapeutic effects.
Materials and methods: This was a substudy of an international investigation of treatment for 6 months or less with desmopressin tablets in children with primary nocturnal enuresis. Medication was dispensed at each visit as required and collected at each subsequent visit. Compliance was determined by pill counts by study staff.
Results: Compliance data were available on 723 patients. Of the patients 81% to 91% ingested all medication as instructed during the initial run-in phases. However, this decreased to 77% and 71% during the first and second 3-month treatment periods, respectively.
Conclusions: Patient motivation and compliance are generally stronger in clinical trials than in clinical practice. However, this study shows that some patients were poorly compliant with medication even at study initiation and only 71% were fully compliant with long-term treatment. Decreased compliance was associated with a lower response rate. Patients should be encouraged to comply fully with treatment to achieve an optimal outcome.