Core outcome domains for trials in autosomal dominant polycystic kidney disease: An international Delphi survey

Rationale & Objective Outcomes reported in trials involving patients with autosomal dominant polycystic kidney disease (ADPKD) are heterogeneous and rarely include patient-reported outcomes. We aimed to identify critically important consensus-based core outcome domains to be reported in trials in ADPKD. Study Design An international 2-round online Delphi survey was conducted in English, French, and Korean languages. Setting & Participants Patients/caregivers and health professionals completed a 9-point Likert scale (7-9 indicating critical importance) and a Best-Worst Scale. Analytical Approach The absolute and relative importance of outcomes were assessed. Comments were analyzed thematically. Results 1,014 participants (603 [60%] patients/caregivers, 411 [40%] health professionals) from 56 countries completed round 1, and 713 (70%) completed round 2. The prioritized outcomes were kidney function (importance score, 8.6), end-stage kidney disease (8.6), death (7.9), blood pressure (7.9), kidney cyst size/growth (7.8), and cerebral aneurysm (7.7). Kidney cyst–related pain was the highest rated patient-reported outcome by both stakeholder groups. Seven themes explained the prioritization of outcomes: protecting life and health, directly encountering life-threatening and debilitating consequences, specificity to ADPKD, optimizing and extending quality of life, hidden suffering, destroying self-confidence, and lost opportunities. Limitations Study design precluded involvement from those without access to internet or limited computer literacy. Conclusions Kidney function, end-stage kidney disease, and death were the most important outcomes to patients, caregivers, and health professionals. Kidney cyst–related pain was the highest rated patient-reported outcome. Consistent reporting of these top prioritized outcomes may strengthen the value of trials in ADPKD for decision making

Caregiver Burden of Autosomal Dominant Polycystic Kidney Disease: A Qualitative StudyPlain-Language Summary

Rationale & Objective: There is limited published research on how autosomal dominant polycystic kidney disease (ADPKD) impacts caregivers. This study explored how caregivers of individuals with ADPKD perceive the burdens placed on them by the disease. Study Design: Qualitative study consisting of focus groups and interviews. Discussions were conducted by trained interviewers using semi-structured interview guides. Setting & Participants: The research was conducted in 14 countries in North America, South America, Asia, Australia, and Europe. Eligible participants were greater than or equal to 18 years old and caring for a child or adult diagnosed with ADPKD. Analytical Approach: The concepts reported were coded using qualitative research software. Data saturation was reached when subsequent discussions introduced no new key concepts. Results: Focus groups and interviews were held with 139 participants (mean age, 44.9 years; 66.9% female), including 25 participants who had a diagnosis of ADPKD themselves. Caregivers reported significant impact on their emotional (74.1%) and social life (38.1%), lost work productivity (26.6%), and reduced sleep (25.2%). Caregivers also reported worry about their financial situation (23.7%). In general, similar frequencies of impact were reported among caregivers with ADPKD versus caregivers without ADPKD, with the exception of sleep (8.0% vs 28.9%, respectively), leisure activities (28.0% vs 40.4% respectively), and work/employment (12.0% vs 29.8%, respectively). Limitations: The study was observational and designed to elicit concepts, and only descriptive analyses were conducted. Conclusions: These findings highlight the unique burden on caregivers in ADPKD, which results in substantial emotional, social, and professional/financial impact

Medical resource utilization and costs associated with autosomal dominant polycystic kidney disease in the USA: a retrospective matched cohort analysis of private insurer data

Tyler Knight,1 Caroline Schaefer,1 Holly Krasa,2 Dorothee Oberdhan,2 Arlene Chapman,3 Ronald D Perrone4 1Covance Market Access Services Inc., Gaithersburg, MD, 2Otsuka Pharmaceutical Development and Commercialization, Inc., Rockville, MD, 3Emory University, Atlanta, GA, 4Tufts Medical Center and Tufts University School of Medicine, Boston, MA, USA Background: Autosomal dominant polycystic kidney disease (ADPKD) results in kidney cyst development and enlargement, resulting in chronic kidney disease (CKD) leading to renal failure. This study sought to determine if ADPKD patients in the early stages of CKD contribute to a sizable economic burden for the US health care system. Methods: This was a retrospective, matched cohort study, reviewing medical resource utilization (MRU) and costs for adults in a US private-payer claims database with a diagnosis code of ADPKD (ICD-9-CM 753.13). ADPKD patients were matched by age grouping (0–17, 18–34, 35–44, 45–54, 55–64, and 65+ years) and sex to controls to understand the burden of ADPKD. Descriptive statistics on 6-month MRU and costs were assessed by CKD stages, dialysis use, or previous renal transplant. Results: The analysis included ADPKD patients in CKD stages 1–5 (n=316 to n=860), dialysis (n=586), and post-transplant (n=615). Mean ages did not differ across CKD stages (range 43–56 years). Men were the majority in the later stages but the minority in the early stages. The proportion of patients with at least one hospitalization increased with CKD stage, (12% to >40% CKD stage 2 to stage 5, dialysis or post-transplant). The majority had at least one hospital outpatient visit and at least one pharmacy claim. Total 6-month per-patient costs were greater among ADPKD patients than in age-matched and sex-matched healthy non-ADPKD controls (P<0.001 for all comparisons). Conclusion: ADPKD patients with normal kidney function are associated with a significant economic burden to the health care system relative to the general population. Any treatments that delay progression to later stages of CKD may provide potential health care cost offsets. Keywords: autosomal dominant polycystic kidney disease, medical resource utilization, chronic kidney diseas

Effects of tolvaptan discontinuation in patients with autosomal dominant polycystic kidney disease: a post hoc pooled analysis

Abstract Background Tolvaptan slows kidney function decline in patients with autosomal dominant polycystic kidney disease (ADPKD) who are at risk of rapid progression. Given that treatment requires commitment to long-term use, we evaluated the effects of tolvaptan discontinuation on the trajectory of ADPKD progression. Methods This was a post hoc analysis of pooled data from two clinical trials of tolvaptan (TEMPO 2:4 [NCT00413777] and TEMPO 3:4 [NCT00428948]), an extension trial (TEMPO 4:4 [NCT01214421]), and an observational study (OVERTURE [NCT01430494]) that enrolled patients from the other trials. Individual subject data were linked longitudinally across trials to construct analysis cohorts of subjects with a tolvaptan treatment duration > 180 days followed by an off-treatment observation period of > 180 days. For inclusion in Cohort 1, subjects were required have ≥ 2 outcome assessments during the tolvaptan treatment period and ≥ 2 assessments during the follow-up period. For Cohort 2, subjects were required to have ≥ 1 assessment during the tolvaptan treatment period and ≥ 1 assessment during the follow-up period. Outcomes were rates of change in estimated glomerular filtration rate (eGFR) and total kidney volume (TKV). Piecewise-mixed models compared changes in eGFR or TKV in the on-treatment and post-treatment periods. Results In the Cohort 1 eGFR population (n = 20), the annual rate of eGFR change (in mL/min/1.73 m2) was -3.18 on treatment and -4.33 post-treatment, a difference that was not significant (P = 0.16), whereas in Cohort 2 (n = 82), the difference between on treatment (-1.89) and post-treatment (-4.94) was significant (P < 0.001). In the Cohort 1 TKV population (n = 11), TKV increased annually by 5.18% on treatment and 11.69% post-treatment (P = 0.06). In Cohort 2 (n = 88), the annual TKV growth rates were 5.15% on treatment and 8.16% post-treatment (P = 0.001). Conclusions Although limited by small sample sizes, these analyses showed directionally consistent acceleration in measures of ADPKD progression following the discontinuation of tolvaptan

OVERTURE: A worldwide, prospective, observational study of disease characteristics in patients with ADPKD

Introduction The course of autosomal dominant polycystic kidney disease (ADPKD) varies greatly among affected individuals, necessitating natural history studies to characterize the determinants and effects of disease progression. Therefore, we conducted an observational, longitudinal study (OVERTURE; NCT01430494) of patients with ADPKD. Methods This prospective study enrolled a large international population (N = 3409) encompassing a broad spectrum of ages (12–78 years), chronic kidney disease (CKD) stages (G1–G5), and Mayo imaging classifications (1A–1E). Outcomes included kidney function, complications, quality of life, health care resource utilization, and work productivity. Results Most subjects (84.4%) completed ≥12 months of follow-up. Consistent with earlier findings, each additional l/m of height-adjusted total kidney volume (htTKV) on magnetic resonance imaging (MRI) was associated with worse outcomes, including lower estimated glomerular filtration rate (eGFR) (regression coefficient 17.02, 95% confidence interval [CI] 15.94–18.11) and greater likelihood of hypertension (odds ratio [OR] 1.25, 95% CI 1.17–1.34), kidney pain (OR 1.22, 95% CI 1.11–1.33), and hematuria (OR 1.35, 95% CI 1.21–1.51). Greater baseline htTKV was also associated with worse patient-reported health-related quality of life (e.g., ADPKD Impact Scale physical score, regression coefficient 1.02, 95% CI 0.65–1.39), decreased work productivity (e.g., work days missed, regression coefficient 0.55, 95% CI 0.18–0.92), and increased health care resource utilization (e.g., hospitalizations, OR 1.48, 95% CI 1.33–1.64) during follow-up. Conclusion Although limited by a maximum 3-year duration of follow-up, this observational study characterized the burden of ADPKD in a broad population and indicated the predictive value of kidney volume for outcomes other than kidney function

Development of the Autosomal Dominant Polycystic Kidney Disease Impact Scale: A New Health-Related Quality-of-Life Instrument.

BackgroundThe impact of autosomal dominant polycystic kidney disease (ADPKD) on health-related quality of life (HRQoL) is not well understood due to a lack of instruments specific to the condition.Study designContent for a new self-administered patient-reported outcome (PRO) questionnaire to assess ADPKD-related HRQoL was developed through clinical expert and patient focus group discussions. The new PRO instrument was administered to study patients with ADPKD to evaluate its reliability and validity.Setting &amp; participants1,674 adult patients with ADPKD participated in this research: 285 patients in focus groups to generate questionnaire content, 15 patients in debriefing interviews to refine the PRO questionnaire, and 1,374 patients to assess the performance and measurement properties of the PRO questionnaire.OutcomeA new PRO questionnaire.ResultsThe ADPKD Impact Scale (ADPKD-IS), consisting of 14 items representing 3 conceptual domains (physical, emotional, and fatigue) plus 4 additional questions, was developed. The instrument's reliability (regarding internal consistency and test-retest consistency) and validity (content and construct) were supported.LimitationsNeed for more responsiveness testing when more data from clinical use become available over time. Complex concepts such as ADPKD-related pain and impact on a patient's HRQoL need further evaluation.ConclusionsThe ADPKD-IS is a new patient-centric tool that reliably and validly provides a standardized method for assessing HRQoL and overall disease burden in patients with ADPKD

OVERTURE: A Worldwide, Prospective, Observational Study of Disease Characteristics in Patients With ADPKD

Introduction: The course of autosomal dominant polycystic kidney disease (ADPKD) varies greatly among affected individuals, necessitating natural history studies to characterize the determinants and effects of disease progression. Therefore, we conducted an observational, longitudinal study (OVERTURE; NCT01430494) of patients with ADPKD. Methods: This prospective study enrolled a large international population (N = 3409) encompassing a broad spectrum of ages (12–78 years), chronic kidney disease (CKD) stages (G1–G5), and Mayo imaging classifications (1A–1E). Outcomes included kidney function, complications, quality of life, health care resource utilization, and work productivity. Results: Most subjects (84.4%) completed ≥12 months of follow-up. Consistent with earlier findings, each additional l/m of height-adjusted total kidney volume (htTKV) on magnetic resonance imaging (MRI) was associated with worse outcomes, including lower estimated glomerular filtration rate (eGFR) (regression coefficient 17.02, 95% confidence interval [CI] 15.94–18.11) and greater likelihood of hypertension (odds ratio [OR] 1.25, 95% CI 1.17–1.34), kidney pain (OR 1.22, 95% CI 1.11–1.33), and hematuria (OR 1.35, 95% CI 1.21–1.51). Greater baseline htTKV was also associated with worse patient-reported health-related quality of life (e.g., ADPKD Impact Scale physical score, regression coefficient 1.02, 95% CI 0.65–1.39), decreased work productivity (e.g., work days missed, regression coefficient 0.55, 95% CI 0.18–0.92), and increased health care resource utilization (e.g., hospitalizations, OR 1.48, 95% CI 1.33–1.64) during follow-up. Conclusion: Although limited by a maximum 3-year duration of follow-up, this observational study characterized the burden of ADPKD in a broad population and indicated the predictive value of kidney volume for outcomes other than kidney function