Development and Assessment of the Psychometric Properties of a Polycystic Liver Disease-specific Patient Reported Outcomes Questionnaire (PLD-Q).

As liver function is preserved, quality of life is the main outcome in PLD. Patient reported outcomes are increasingly utilized to assess treatment efficacy & can include any endpoint derived from patient reports & are usually assessed by questionnaire. Several existing generic questionnaires assess gastrointestinal symptoms, but include irrelevant items for polycystic liver disease (PLD) & do not examine relevant extra-abdominal symptoms. Also, a questionnaire that assesses the full range of PLD related problems is more likely to be responsive to changes after treatment initiation. Therefore, a tool that accurately detects changes in PLD symptoms is required.

The development and first steps of validation of this questionnaire are already completed in Netherlands. We will further develop this questionnaire for English speaking patients and validate it in Mayo Clinic cohorts.

The study contains three phases. Phase 1: pilot testing of the directly translated questionnaire (from dutch into english) in a small group of polycystic liver disease (PLD) patients. We will include both symptomatic & asymptomatic patients (i.e. from mild to severe PLD). Phase 2: further refinement of the questionnaire using the results of the pilot test and input of Mayo patient and clinician focus groups. Phase 3: Further validation in a large cohort of 200 PLD patients with (1) comparison with 200 controls without PLD, (2) cross-sectional correlation with total liver (TLV) & kidney volumes (TKV), (3) comparing ADPKD patients with & without PLD (5) against other validated questionnaires (e.g. SF36) & (5) development of a custom "Worry Questionnaire" examining disease-related worries & concerns. Finally, longitudinal analyses will be performed to assess PLD-Q sensitivity to change in symptoms. Statistical & psychometric analyses will be provided by Mayo Clinic quality of life Research group, & developed in accordance with Food and Drug Administration (FDA) guidance on patient-reported outcome measures in consultation with their Study Endpoints & Labeling Development Division.