Pain and Health-Related Quality of Life in Autosomal Dominant Polycystic Kidney Disease: Results from a National Patient-Powered Registry

Rationale & Objective

Autosomal dominant polycystic kidney disease (ADPKD) affects health-related quality of life (HRQoL) including pain, discomfort, fatigue, emotional distress, and impaired mobility. Stakeholders prioritized kidney cyst-related pain as an important core outcome domain in clinical trials, leading to the development of disease-specific assessment tools.

Study Design

The ADPKD Registry is hosted online with multiple disease-specific patient-reported outcomes modules to characterize the patient experience in the United States.

Setting & Participants

The ADPKD Registry allows consented participants access to a Core Questionnaire that includes demographics, comorbid conditions, current symptoms, and kidney function. Participants complete subsequent modules on a 3-month schedule, including 2 validated HRQoL tools, the ADPKD-Pain and Discomfort Scale (ADPKD-PDS), the ADPKD Impact Scale (ADPKD-IS) and a Healthcare Access and Utilization module.

Exposures

Patient-reported latest estimated glomerular filtration rate or creatinine used to calculate stage of chronic kidney disease.

Outcomes

Health-related quality of life, measured using validated ADPKD-specific tools; access to polycystic kidney disease-specific health care.

Analytical Approach

For the 2 HRQoL tools, scores were calculated for physical, emotional, and fatigue domains; pain severity; and pain interference (based on the licensed user manuals). Associations to health care access were also assessed.

Results

By July 2022, 1,086 individuals with ADPKD completed at least 1 of the HRQoL modules, and 319 completed 4 over a year. Participants were an average age of 53. In total, 71% were women, and 91% were White, with all chronic kidney disease (CKD) stages represented. In total, 2.5% reported being treated with dialysis, and 23% had a kidney transplant. CKD stage 4/5 participants reported the most dull kidney pain, whereas sharp kidney pain was evenly distributed across early CKD stages. Dull kidney pain had an impact on sleep regardless of CKD stage. There was a strong positive correlation between the ADPKD-PDS and ADPKD-IS. Patients with a neutral or positive HRQoL were less likely to have been denied access to imaging or other care.

Limitations

Currently, all the information collected is patient reported without health record validation of clinical variables.

Conclusions

Use of the HRQoL tools in the ADPKD Registry provided a broad cross-sectional assessment in the United States and provided granular information on the burden of pain across the CKD spectrum in ADPKD. The ADPKD Registry allowed assessment of ADPKD impact in a community that experiences decline in health and kidney function over decades.

Patient-Reported Outcomes Measures, Polycystic Kidney Disease Burden, and Outcomes in Autosomal Dominant Polycystic Kidney Disease

Rationale & Objective

Using OVERTURE (NCT01430494) study data on patient-perceived health, health care utilization, and productivity in autosomal dominant polycystic kidney disease (ADPKD), this research was conducted to characterize the burden of illness in patients with ADPKD and assess whether patient-reported outcome (PRO) assessment scores predict clinical and health-economic outcomes.

Study Design

Data were analyzed from a prospective, observational study.

Setting & Participants

The study cohort comprised 3,409 individuals with ADPKD in 20 countries who were aged 12-78 years and were in chronic kidney disease (CKD) stages G1-G5 and Mayo risk subclasses 1A-1E.

Predictors

Scores on PRO instruments, including disease-specific assessments [ADPKD-Impact Scale (ADPKD-IS), and ADPKD-Urinary Impact Scale (ADPKD-UIS)] and generic measures were assessed.

Outcomes

Clinical variables [eg, height-adjusted total kidney volume (htTKV), estimated glomerular filtration rate (eGFR), and abdominal girth] and health-economic outcomes were assessed.

Analytical Approach

Associations among variables were evaluated using Spearman correlations, logistic regression, and generalized linear mixed effects repeated measures models.

Results

Baseline CKD stage and Mayo risk classification showed little correlation with baseline PRO scores; however, scores on disease-specific instruments and measures of physical functioning were worse at more severe CKD stages. PRO scores predicted hospitalizations and sick days at 6-18 months, with strongest associations noted for the ADPKD-IS. PRO scores were not associated with htTKV and eGFR, but worse PRO scores were associated with greater abdominal girth. Poor baseline ADPKD-IS scores were positively associated with occurrence of ADPKD-related symptoms up to 18 months, including kidney pain (OR, 5.30; 95% CI, 2.75-10.24), hematuria (OR, 4.58; 95% CI, 1.99-10.53), and urinary tract infection (OR, 4.41; 95% CI, 1.93-10.11; P < 0.001 for all).

Limitations

A limitation of the study was the maximum 18 months of follow-up available to assess outcomes.

Conclusions

PRO scores predicted clinical and health-economic outcomes, such as hospitalization and absence from work, underscoring the importance of quality of life assessment of individuals with ADPKD.

Plain-Language Summary

Patient-reported outcomes (PROs) are increasingly recognized as important parameters for assessing the clinical and humanistic burden of autosomal dominant polycystic kidney disease (ADPKD). We analyzed data from the observational OVERTURE study to better characterize disease impact on quality of life and determine whether patient-perceived burden might predict outcomes. Scores on PRO assessment instruments predicted hospitalizations and sick days at 6-18 months, with associations strongest for the disease-specific ADPKD-Impact Scale. Compared to patients who rated their health-related quality of life as good, those with poor baseline scores were significantly more likely to report ADPKD-related signs and symptoms up to 18 months of follow-up. These findings support using disease-specific PRO assessment instruments to assess and predict the impact of ADPKD.

Understanding Patients' Experiences with Borderline Personality Disorder: Qualitative Interviews

Background

Patient perspectives of living with borderline personality disorder (BPD) are not traditionally captured in the literature. To overcome this gap, we explored participants' experiences with BPD to gain a better understanding of symptoms and impacts related to the condition.

Methods

Two experienced researchers conducted semistructured interviews with a subset of participants from a randomized controlled trial evaluating a BPD treatment. The interview study was independent from the trial. Interviews focused on participants' experiences with BPD prior to the trial, including the symptoms and impacts of BPD. Interview transcripts were analyzed to identify dominant trends and generate patterns in the way participants described their experiences with BPD.

Results

A total of 50 adults with BPD participated in the interview study. The mean age of the participants was 28.5 years (range, 18-53 years) and 72.0% were female. All participants described having difficulties with extreme emotional responses and interpersonal relationships, and most participants reported experiencing issues with self-image, impulsivity, suspiciousness/distrust, feelings of emptiness, and anger. The symptoms that were most bothersome to participants were extreme moods or emotional responses and a pattern of unstable personal relationships. All participants remarked that their BPD-related symptoms negatively impacted their interpersonal relationships, and nearly two-thirds of the sample reported that the impact of BPD on their relationships was the most bothersome. Additionally, more than half of the participants discussed impacts on work or school, memory or thinking, self-care, and financial and legal issues.

Conclusion

Participants reported that the most bothersome symptoms of BPD were those related to extreme moods or emotional responses and interpersonal relationships. Participants similarly described the impact of BPD on their interpersonal relationships as the most bothersome. Overall, participant perspectives from this study indicate that the burden of BPD is significant and new treatments tailored to patients' real-world needs are warranted.

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

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.

Tolvaptan and Kidney Function Decline in Older Individuals With Autosomal Dominant Polycystic Kidney Disease: A Pooled Analysis of Randomized Clinical Trials and Observational Studies

Rationale & Objective

Tolvaptan is indicated for treatment of patients with autosomal dominant polycystic kidney disease (ADPKD) at risk of rapid progression. Participants aged 56-65 years constituted a small proportion of the Replicating Evidence of Preserved Renal Function: an Investigation of Tolvaptan Safety and Efficacy in ADPKD (REPRISE) trial population. We assessed effects of tolvaptan on estimated glomerular filtration rate (eGFR) decline in participants aged >55 years.

Study Design

This was a pooled data analysis from 8 studies of tolvaptan or non-tolvaptan standard of care (SOC).

Setting & Participants

Participants aged >55 years with ADPKD were included. Data on participants in >1 study were linked longitudinally for maximum follow-up duration, with matching for age, sex, eGFR, and chronic kidney disease (CKD) stage to minimize confounding.

Interventions

Tolvaptan or non-tolvaptan SOC.

Outcomes

Treatment effects on annualized eGFR decline were compared using mixed models with fixed effects for treatment, time, treatment-by-time interaction, and baseline eGFR.

Results

In the pooled studies, 230 tolvaptan-treated and 907 SOC participants were aged >55 years at baseline. Ninety-five participant pairs from each treatment group were matched, all in CKD G3 or G4, ranging from 56.0 to 65.0 years (tolvaptan) or from 55.1 to 67.0 years (SOC). The eGFR annual decline rate was significantly reduced by 1.66 mL/min/1.73 m² (95% CI, 0.43-2.90; P = 0.009) in the tolvaptan group compared with SOC (-2.33 versus -3.99 mL/min/1.73 m²) over 3 years.

Limitations

Limitations include potential bias because of study population differences (bias risk was reduced through matching and multiple regression adjustment); vascular disease history data was not uniformly collected, and therefore not adjusted; and natural history of ADPKD precludes evaluating certain clinical endpoints within the study time frame.

Conclusions

In individuals aged 56-65 years with CKD G3 or G4, compared to a SOC group with mean GFR rate of decline ≥3 mL/min/1.73 m²/year, tolvaptan was associated with efficacy similar to that observed in the overall indication.

Funding

Otsuka Pharmaceutical Development & Commercialization, Inc (Rockville, MD).

Trial Registration

TEMPO 2:4 (NCT00413777); phase 1 tolvaptan trial (no NCT number; trial number 156-06-260); phase 2 tolvaptan trial (NCT01336972); TEMPO 4:4 (NCT01214421); REPRISE (NCT02160145); long-term tolvaptan safety extension trial (NCT02251275); OVERTURE (NCT01430494); HALT Progression of Polycystic Kidney Disease (HALT-PKD) study B (NCT01885559).

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 a Patient-Reported Outcomes Tool to Assess Pain and Discomfort in Autosomal Dominant Polycystic Kidney Disease

BACKGROUND

Pain has been identified as a core outcome for individuals with autosomal dominant polycystic kidney disease (ADPKD), but no disease-specific pain assessment has been developed using current development methodology for patient-reported outcomes (PRO) instruments. We developed and validated an ADPKD-specific pain questionnaire: the ADPKD Pain and Discomfort Scale (ADPKD-PDS).

METHODS

Conceptual underpinnings were drawn from literature review, concept elicitation, expert consultation, and measurement performance. In the qualitative analysis phase, concepts were elicited from focus groups of adults with ADPKD, and the resulting draft instrument was refined using cognitive debriefing interviews with individuals with ADPKD. For quantitative analysis, adults with ADPKD completed the draft instrument and other PRO tools in an online survey, and a follow-up survey was conducted 3-4 weeks later. Survey responses were analyzed for item-level descriptive statistics, latent model fit statistics, item discrimination, item- and domain-level psychometric statistics, test-retest reliability, responsiveness to change, and convergent validity.

RESULTS

In the qualitative phase, 46 focus groups were conducted in 18 countries with 293 participants. Focus groups described three conceptually distinct types of ADPKD-related pain and discomfort (dull kidney pain, sharp kidney pain, and fullness/discomfort). In the quantitative phase, 298 adults with ADPKD completed the online survey, and 108 participants completed the follow-up survey. After iterative refinement of the instrument, latent variable measurement models showed very good fit (comparative fit and nonnormed fit indices both 0.99), as did item- and domain-level psychometric characteristics. The final ADPKD-PDS contains 20 items assessing pain severity and interference with activities over a 7-day recall period.

CONCLUSIONS

The ADPKD-PDS is the first validated tool for systematically assessing pain and discomfort in ADPKD.

Caregiver Burden of Autosomal Dominant Polycystic Kidney Disease: A Qualitative Study

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.

A disease progression model estimating the benefit of tolvaptan on time to end-stage renal disease for patients with rapidly progressing autosomal dominant polycystic kidney disease

Background

Tolvaptan was approved in the United States in 2018 for patients with autosomal dominant polycystic kidney disease (ADPKD) at risk of rapid progression as assessed in a 3-year phase 3 clinical trial (TEMPO 3:4). An extension study (TEMPO 4:4) showed continued delay in progression at 2 years, and a trial in patients with later-stage disease (REPRISE) provided confirmatory evidence of efficacy. Given the relatively shorter-term duration of the clinical trials, estimating the longer-term benefit associated with tolvaptan via extrapolation of the treatment effect is an important undertaking.

Methods

A model was developed to simulate a cohort of patients with ADPKD at risk of rapid progression and predict their long-term outcomes using an algorithm organized around the Mayo Risk Classification system, which has five subclasses (1A through 1E) based on estimated kidney growth rates. The model base-case population represents 1280 patients enrolled in TEMPO 3:4 beginning in chronic kidney disease (CKD) stages G1, G2, and G3 across Mayo subclasses 1C, 1D, and 1E. The algorithm was used to predict longer-term natural history health outcomes. The estimated treatment effect of tolvaptan from TEMPO 3:4 was applied to the natural history to predict the longer-term treatment benefit of tolvaptan. For the cohort, analyzed once reflecting natural history and once assuming treatment with tolvaptan, the model estimated lifetime progression through CKD stages, end-stage renal disease (ESRD), and death.

Results

When treated with tolvaptan, the model cohort was predicted to experience a 3.1-year delay of ESRD (95% confidence interval: 1.8 to 4.4), approximately a 23% improvement over the estimated 13.7 years for patients not receiving tolvaptan. Patients beginning tolvaptan treatment in CKD stages G1, G2, and G3 were predicted to experience estimated delays of ESRD, compared with patients not receiving tolvaptan, of 3.8 years (21% improvement), 3.0 years (24% improvement), and 2.1 years (28% improvement), respectively.

Conclusions

The model estimated that patients treated with tolvaptan versus no treatment spent more time in earlier CKD stages and had later onset of ESRD. Findings highlight the potential long-term value of early intervention with tolvaptan in patients at risk of rapid ADPKD progression.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-022-02956-8.

Pooled Data Analysis of the Long-Term Treatment Effects of Tolvaptan in ADPKD

Introduction

Methods

Results

Conclusion

Developing a Conceptual Disease Model of Patient Experiences and Identifying Patient-Reported Clinical Outcome Assessments for Use in Trials of Treatments for Focal Onset Seizures

PURPOSE

To identify concepts important to understanding the experiences of adults with focal onset seizures (FOS) and evaluate clinical outcome assessments (COAs) for measuring these concepts in clinical trials of treatments for FOS.

METHODS

A search of published qualitative research, clinical trials, and approved product labels for FOS treatments was performed to develop a conceptual disease model (CDM) of patients' experience of living with FOS. Concepts of interest (COI) were selected, and a second literature search was conducted to identify COAs measuring these concepts. Ten COAs were selected and reviewed to document their development process, evidence of measurement properties, and methods for interpreting change scores using criteria proposed in regulatory guidelines for patient-reported outcomes to support label claims.

RESULTS

Concepts identified from the published literature (13 articles, 1 conference abstract), 24 clinical trials, and 8 product labels were included in a novel CDM. Impacts on physical, cognitive, and social and emotional function were chosen as COI for evaluating treatment outcomes for FOS; the additional concept of social support and coping strategies was chosen to understand patients' lived experiences. From 51 unique COAs identified, 10 were selected based on their potential coverage of the COI; some symptom severity and health-related quality of life (HRQoL) COAs covered multiple COI. Of these 10, 8 COAs evaluated impacts/limitations on physical function, 8 measured social and emotional impacts, and 5 assessed social support and coping strategies. While most assessments had gaps in evidence validating their measurement properties, 2 COAs measuring symptom severity and 1 COA measuring HRQoL had evidence confirming their potential utility in clinical trials to support label claims.

CONCLUSION

This research provides insights into the experience of patients with FOS and identifies COAs that measure concepts considered to support endpoints in clinical trials for FOS.

Polycystic Kidney Disease–Related Disease Burden in Adolescents With Autosomal Dominant Polycystic Kidney Disease: An International Qualitative Study

Rationale & Objective

Little is known about symptoms and disease impacts in adolescents with autosomal dominant polycystic kidney disease (ADPKD). The objective of the study was to explore these issues from the adolescent patient’s perspective.

Study Design

Observational, qualitative study.

Setting & Participants

Eligible participants were 12-17 years old and had a diagnosis of ADPKD. Semi-structured interviews were conducted in 18 cities in 13 countries to elicit participant experiences of ADPKD-related symptoms and physical, social, and emotional impacts.

Analytical Approach

Interviews were recorded, transcribed, and coded. Symptom and impact frequencies from the interviews were calculated, and representative quotes concerning elicited concepts were collated.

Results

Thirty-three participants (mean age, 14.6 years; 42.4% female) completed interviews. Frequently reported symptoms included urinary urgency (n = 10; 30.3%) and back pain (n = 9; 27.3%). Consistent with previous findings in adults, participants experienced 3 primary types of pain: dull kidney pain, severe or sharp kidney pain, and a feeling of fullness and/or discomfort. Reported disease impacts included avoiding sports and physical activity (n = 10; 30.3%), missing school (n = 6; 18.2%) and social activities (n = 6; 18.2%), and feeling worried (n = 6; 18.2%), sad (n = 4; 12.1%), or frustrated (n = 3; 9.1%) about the disease and their future. Approximately one-fifth of participants (n = 7; 21.2%) reported that they were bothered or impacted by dietary limitations (primarily the need for reduced sodium intake and increased water intake).

Limitations

The study had a small sample size. The researchers were unable to conduct focus groups with participants because of parental preferences.

Conclusions

The findings from this exploratory study indicate that a substantial proportion of adolescents with ADPKD experience physical, social, and emotional impacts from their disease.

Disconnect in Assessments of Autosomal Dominant Polycystic Kidney Disease Burden Between Patients and Physicians: A Survey Study

Background

Autosomal dominant polycystic kidney disease (ADPKD) is a rare inherited kidney disorder with considerable symptom burden and negative effects even in early-stage disease. Patients' reporting of ADPKD symptom burden may differ from physicians' impressions. In this quantitative, cross-section survey study, we evaluated patient and physician assessments of symptom burden at early- and late-stage ADPKD.

Methods

In the United States, 300 patients with ADPKD and 155 physicians treating patients with ADPKD completed online surveys administered by Kantar. Disease stage was categorized as early (chronic kidney disease [CKD] stages 1-3) or late (stages 4-5). Patients completed the Work Productivity and Activity Impairment Questionnaire and reported current disease symptoms. Patients and physicians assessed impacts of ADPKD on daily life and burden of specific symptoms. Statistical analyses compared patient versus physician responses stratified by early- versus late-stage ADPKD.

Results

We found that impairment in work productivity was statistically greater in late- versus early-stage CKD. Compared with physicians' impressions, patients were more likely at early stages and less likely at later stages to report a moderate/strong impact of ADPKD on daily life. Among patients, 74% with early- and 88% with late-stage disease reported that ADPKD caused them to modify their daily lives. In early-stage disease, patients reported a statistically greater burden from feeling exhausted and less burden from dull kidney pain, cardiovascular problems, high blood pressure, and liver cysts than physicians assumed. At later stages, patients reported feeling exhausted and skeletal/joint pain as more burdensome, and frequent urination, high blood pressure, liver cysts, and hematuria as less burdensome, compared with physicians' impressions.

Conclusion

The results of this survey study demonstrate a disconnect between patients' experiences and physicians' awareness of the burden of ADPKD and highlight the need for more patient/physician discussion of symptoms and disease management.

Excess healthcare costs in patients with autosomal dominant polycystic kidney disease by renal dysfunction stage

AIM

To build upon previous outdated studies by comprehensively assessing the direct healthcare burden of autosomal dominant polycystic kidney disease (ADPKD).

MATERIALS AND METHODS

Patients with ≥2 diagnoses for ADPKD (ADPKD cohort) were identified in the US fee-for-use IBM Truven Health Analytics MarketScan Commercial Claims and Encounters and IBM Truven Health Analytics MarketScan Medicare Supplemental databases (01 January 2015-31 December 2017) and matched (1:3) to controls without ADPKD (non-ADPKD cohort). The index date was the last calendar date followed by 12 months continuous enrollment (study period). Patients with ADPKD were stratified into one of seven mutually exclusive groups based on chronic kidney disease (CKD) stages (I-V), end-stage renal disease requiring renal replacement therapy (ESRD-RRT), and unknown stage.

RESULTS

During the 12-month study period, patients with ADPKD incurred significantly higher total healthcare costs than those without ADPKD (mean cost difference = $22,879 per patient per year [PPPY]; p < .001). Besides CKD stages I and II, total healthcare cost differences increased as patients progressed beyond CKD stage III, with the greatest difference observed among patients with ESRD-RRT. Total healthcare cost differences between cohorts were more pronounced in subgroups of patients with hypertension ($29,347) and with high risk of rapid progression ($39,976). Similar results were observed in the Medicare Supplemental population, with a total mean cost difference of $42,694 PPPY (p < .001); cost difference was also higher in the hypertension ($46,461 PPPY) and high risk of rapid progression ($45,708 PPPY) subgroups.

LIMITATIONS

Results may not be representative of the overall ADPKD US population; CKD stage was based on diagnosis and procedure codes; criteria used to identify ADPKD at risk of rapid progression did not rely on laboratory values; there may be billing inaccuracies and omissions in health insurance claims data.

CONCLUSIONS

This study demonstrated the substantial healthcare costs associated with ADPKD, which increased as patients progressed through more severe CKD stages.

Review of Clinical Outcome Assessments in Pediatric Attention-Deficit/Hyperactivity Disorder

PURPOSE

Various clinical outcome assessments (COAs) are used in clinical research to assess and monitor treatment efficacy in pediatric attention-deficit/hyperactivity disorder (ADHD) trials. It is unclear whether the concepts assessed are those that are important to patients and their caregivers. The concepts measured by commonly used COAs in this population have not been explicitly compared.

METHODS

We conducted reviews of the qualitative literature to extract information on pediatric ADHD-related concepts reported by pediatric patients, parents, and teachers. Using these concepts, we developed a conceptual framework of pediatric ADHD using both the Diagnostic and Statistical Manual of Mental Disorders (DSM) criteria and the additional symptoms and behavioral impacts identified in the literature. We searched for COAs that have been used in pediatric ADHD research and mapped their items based on their conceptual underpinning.

RESULTS

Of the 27 COAs found in the empirical literature, 4 COAs assessed only DSM symptoms. The most comprehensive coverage of our conceptual framework was seen in the Swanson, Nolan, and Pelham Rating Scale-DSM-IV (SNAP-IV). Eighteen COAs were used in at least 1 clinical trial: ADHD-Rating Scale-IV (ADHD-RS-IV) was used most often (n=77), followed by SNAP-IV (n=50), Swanson, Kotkin, Agler, M-Flynn, and Pelham Scale (SKAMP; n=31), Weiss Functional Impairment Rating Scale (WFIRS; n=24), and Vanderbilt ADHD Diagnostic Rating Scale (VADRS; n=15).

CONCLUSION

We identified symptoms and behavioral impacts from qualitative studies in pediatric ADHD that are not included in DSM-based criteria. Most COAs used in pediatric ADHD clinical trials measure only those symptoms listed in the DSM. While these COAs can measure symptom severity, they may not assess the full range of symptoms and impacts important to patients and their caregivers. Future research is needed to measure all concepts important to patients and caregivers within ADHD clinical trials.

P0037POPULATION CHARACTERISTICS ACROSS AN EXPANDED POOLED DATABASE OF MULTIPLE AUTOSOMAL DOMINANT POLYCYSTIC KIDNEY DISEASE CLINICAL STUDIES

Background and Aims

Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary kidney disease and the fourth-leading cause of kidney failure. Over the past two decades, various studies have been conducted to characterize the natural history of ADPKD and investigate impacts of potential treatments on disease progression. Previously, we created a pooled longitudinal database of unique subjects from nine studies to evaluate and analyze outcomes. The database was expanded to include data from two recent tolvaptan (TOL) trials (156-13-210 and 156-13-211). Here, we describe the baseline characteristics of the expanded pooled population.

Method

Data from 11 ADPKD studies (from 2001 to 2018, sponsored by Otsuka or National Institutes of Health) were combined and divided into two groups: TOL and standard of care (SOC). TOL consisted of trial subjects initiating treatment in one of seven trials (156-04-250, 156-04-251, 156-06-260, 156-09-284, 156-09-290, 156-08-271, and 156-13-210); SOC included subjects from placebo arms of two TOL randomized trials (156-04-251 and 156-09-290), all standard blood pressure control arms in the HALT-PKD trials, and subjects from two observational studies (156-10-291 and CRISP). Subjects in the placebo arm of study 156-13-210 received TOL for 5 weeks before randomization and were therefore included in the TOL group. Eligible subjects who completed an early TOL study continued TOL treatment in the extension study 156-08-271 and/or in a second extension study 156-13-211. Estimated glomerular filtration rate (eGFR) was calculated in all studies using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. Total kidney volume (TKV) was measured by magnetic resonance imaging and available in all studies except 156-13-210, 156-13-211, and HALT-PKD study B.

Results

The pooled analysis included 7,117 eligible subjects (TOL: 2,928; SOC: 4,189) from the United States (47.5%) and other countries. The two cohorts had similar age (mean age, 43.6 vs. 44.1 years) and sex distribution (50.5% male vs. 45.2% male). The TOL group had more white subjects (90.5% vs. 80.7%) and fewer Hispanic subjects (4.0% vs. 12.6%), a lower baseline mean eGFR (60 vs. 70 mL/min/1.73 m2), more in chronic kidney disease (CKD) stage 3 or above (58.1% vs. 41.0%), and more frequent history of signs of rapid disease progression (e.g., nephrolithiasis, hematuria, urinary tract infection). Among 4,917 subjects with TKV assessments, mean baseline TKV was higher in the TOL group (1,817 mL) compared with SOC (1,627 mL).

Conclusion

In this large, longitudinal database of unique subjects with ADPKD, distinct differences exist in some baseline characteristics of the TOL and SOC groups. Compared with the previous database, the expanded database doubled the size of the TOL group and included more subjects who were older and with advanced chronic kidney disease stage. This database provides a diverse ADPKD population to assess outcomes.

SO093LONGITUDINAL DATA ON TREATMENT DURATION AND COMPLIANCE FROM AUTOSOMAL DOMINANT POLYCYSTIC KIDNEY DISEASE CLINICAL TRIALS WITH TOLVAPTAN

Background and Aims : Observation of impactful clinical outcomes in a clinical trial setting for ADPKD is challenging due to the life-long progressive nature of ADPKD and longer-term associated outcomes of interest in this population (e.g., renal function decline, cardiovascular events, and mortality). Since 2004, the tolvaptan (TOL) clinical trial program enrolled subjects in multiple clinical studies with the opportunity to enroll in subsequent clinical trials for treatment and outcomes evaluation.

Method : Data from 6 ADPKD studies (protocols 156-04-250, 156-04-251, 156-06-260, 156-09-284, 156-09-290, 156-08-271) were pooled and evaluated over time for overall treatment duration, treatment time, and treatment gaps. Treatment duration for the individual clinical trials ranged from 1 week to up to 3 years.

Results : Overall, 1,437 subjects received TOL in these ADPKD clinical trials. For these subjects, the mean overall treatment duration was 4.1 years (3.8 years on treatment) with a maximum of 9.7 years (9.0 years on treatment). In this cohort, 513 subjects (35.7%) received TOL treatment for more than 5 years. Mean treatment compliance was 94.1%. Overall, 723 subjects (50.3%) received TOL treatment in ≥2 trials, with a median treatment gap duration between trials of 0.1 years (maximum, 5.6 years). At least 7 years of follow-up data are available for estimated glomerular filtration rate in 241 subjects (mean at baseline, 78.6 mL/min/1.73m2) and for total kidney volume in 130 subjects (mean at baseline, 1,816.9 mL).

Conclusion : This analysis provides longitudinal follow-up over an extended timeframe in a large number of subjects treated with TOL, with the greatest number of subjects being enrolled in clinical trials enriched for rapidly progressing ADPKD. Treatment compliance over years was reasonably good despite treatment gaps.

A Randomized Trial of Modified-Release Versus Immediate-Release Tolvaptan in ADPKD

Introduction

Tolvaptan, for treatment of autosomal dominant polycystic kidney disease (ADPKD), is provided as immediate-release (IR) tablets administered twice daily in split-dose regimens to suppress urine osmolality to <300 mOsm/kg. A modified-release (MR) formulation was developed for once-daily (QD) dosing to increase compliance and mitigate urinary symptom burden. This phase 2, dose-ranging study (NCT01210560) compared pharmacokinetics, pharmacodynamics, and tolerability of several MR regimens with IR in patients with ADPKD.

Methods

This was a multicenter, parallel-arm, randomized, crossover, double-blind, placebo-controlled trial. Each of 2 study arms had 12 subjects and 3 crossover periods. Dose regimens were administered for 7 days; placebo-masked QD versus split-dose treatments. Endpoints included pharmacokinetic parameters, percentage of subjects with urine osmolality <300 mOsm/kg, urine volume, number of daily urine voids, and tolerability.

Results

Tolvaptan MR 20 to 120 mg exhibited dose-proportional pharmacokinetics. Percentage of subjects with spot urine osmolality <300 mOsm/kg increased with dose, with tolvaptan MR 120 mg and IR 90+30 mg each suppressing 91.7% of subjects below this level. Urinary burden on the ADPKD Nocturia Quality of Life, ADPKD Urinary Urgency, and ADPKD Urinary Frequency Questionnaires correlated with tolvaptan exposure, with high interindividual variability in responses. Changes in questionnaire scores were sensitive to changes in urine volume but not proportional to volume change, reflecting differences in subject tolerance to increased urine volume.

Conclusion

Tolvaptan MR exhibited predictable and dose-proportional pharmacokinetics and no improvement in tolerability versus tolvaptan IR. Tolerability of the urinary effects of treatment within the high-dose MR and IR groups exhibited substantial interindividual variability.

The societal economic burden of autosomal dominant polycystic kidney disease in the United States

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD) is one of the most common inherited kidney diseases characterized by progressive development of renal cysts and numerous extra-renal manifestations, eventually leading to kidney failure. Given its chronic and progressive nature, ADPKD is expected to carry a substantial economic burden over the course of the disease. However, there is a paucity of evidence on the impact of ADPKD from a societal perspective. This study aimed to estimate the direct and indirect costs associated with ADPKD in the United States (US).

METHODS

A prevalence-based approach using data from scientific literature, and governmental and non-governmental organizations was employed to estimate direct healthcare costs (i.e., medical services, prescription drugs), direct non-healthcare costs (i.e., research and advocacy, donors/recipients matching for kidney transplants, transportation to/from dialysis centers), and indirect costs (i.e., patient productivity loss from unemployment, reduced work productivity, and premature mortality, caregivers' productivity loss and healthcare costs). The incremental costs associated with ADPKD were calculated as the difference between costs incurred over a one-year period by individuals with ADPKD and the US population. Sensitivity analyses using different sources and assumptions were performed to assess robustness of estimates and account for variability in published estimates.

RESULTS

The estimated total annual costs attributed to ADPKD in 2018 ranged from $7.3 to $9.6 billion in sensitivity analyses, equivalent to $51,970 to $68,091 per individual with ADPKD. In the base scenario, direct healthcare costs accounted for $5.7 billion (78.6%) of the total $7.3 billion costs, mostly driven by patients requiring renal replacement therapy ($3.2 billion; 43.3%). Indirect costs accounted for $1.4 billion (19.7%), mostly driven by productivity loss due to unemployment ($784 million; 10.7%) and reduced productivity at work ($390 million; 5.3%). Total excess direct non-healthcare costs were estimated at $125 million (1.7%).

CONCLUSIONS

ADPKD carries a considerable economic burden, predominantly attributed to direct healthcare costs, the majority of which are incurred by public and private healthcare payers. Effective and timely interventions to slow down the progression of ADPKD could substantially reduce the economic burden of ADPKD.

Family and Caregiver Spillover Effects in Cost-Utility Analyses of Alzheimer's Disease Interventions

BACKGROUND AND OBJECTIVE

Alzheimer's disease or dementia can impose a significant burden on family and other informal caregivers. This study investigated how the inclusion of family/informal caregiver spillover effects in a cost-utility analysis may influence the reported value of Alzheimer's disease/dementia interventions.

METHODS

We used PubMed to identify Alzheimer's disease or dementia cost-utility analyses published from 1 January, 2000 to 31 March, 2018. We reviewed and abstracted information from each study using a two-reader consensus process. We investigated the frequency and methods in which family/caregiver spillover costs and health effects were incorporated into cost-utility analyses, and examined how their inclusion may influence the reported incremental cost-effectiveness ratios.

RESULTS

Of 63 Alzheimer's disease/dementia cost-utility analyses meeting inclusion criteria, 44 (70%) considered at least some family/caregiver spillover costs or health effects. Thirty-two studies incorporated spillover costs only, two incorporated spillover health effects only, and ten incorporated both. The most common approach for accounting for spillover was adding informal caregiving time costs to patient costs (n = 36) and adding informal caregiver quality-adjusted life-years to patient values (n = 7). In a subset of 33 incremental cost-effectiveness ratio pairs from 19 studies, incorporating spillover outcomes made incremental cost-effectiveness ratios more favorable (n = 15; 45%) or kept the intervention cost saving (n = 13; 39%) in most cases. In fewer cases, including spillover increased incremental cost-effectiveness ratios (n = 2; 6%), kept the intervention dominated [more costs/less quality-adjusted life-years] (n = 2; 6%), or changed incremental cost-effectiveness ratio from dominated to less cost/less quality-adjusted life-years (n = 1; 3%). In 11 cases (33%), adding spillover effects into analyses resulted in a lower incremental cost-effectiveness ratio that crossed a common cost-effectiveness threshold, which could have downstream implications for programs or policies that are adopted based on cost-effectiveness analysis results.

DISCUSSION

Most Alzheimer's disease/dementia cost-utility analyses incorporated spillover costs, often as caregiver time costs, but considered spillover health impacts less often. In about 85% of the analyses, including Alzheimer's disease/dementia spillover cost or health effects decreased incremental cost-effectiveness ratios or kept the intervention cost saving. The broader value of an Alzheimer's disease/dementia intervention to society may in some cases be underestimated without considering these spillover effects on family and informal caregivers.

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

BACKGROUND

The 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 DESIGN

Content 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 & PARTICIPANTS

1,674 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.

OUTCOME

A new PRO questionnaire.

RESULTS

The 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.

LIMITATIONS

Need 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.

CONCLUSIONS

The 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.

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

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.

Short-term Effects of Tolvaptan in Individuals With Autosomal Dominant Polycystic Kidney Disease at Various Levels of Kidney Function

BACKGROUND

A recent study showed that tolvaptan, a vasopressin V2 receptor antagonist, decreased total kidney volume (TKV) growth and estimated glomerular filtration rate (GFR) loss in autosomal dominant polycystic kidney disease (ADPKD) with creatinine clearance≥60mL/min. The aim of our study was to determine whether the renal hemodynamic effects and pharmacodynamic efficacy of tolvaptan in ADPKD are dependent on GFR.

STUDY DESIGN

Clinical trial with comparisons before and after treatment.

SETTING & PARTICIPANTS

Patients with ADPKD with a wide range of measured GFRs (mGFRs; 18-148 mL/min) in a hospital setting.

INTERVENTION

Participants were studied at baseline and after 3 weeks of treatment with tolvaptan given in increasing dosages, if tolerated (doses of 60, 90, and 120mg/d in weeks 1, 2, and 3, respectively).

OUTCOMES

Change in markers for aquaresis (free-water clearance, urine and plasma osmolality, 24-hour urine volume, and plasma copeptin) and kidney injury (TKV and kidney injury biomarkers).

MEASUREMENTS

GFR was measured by (125)I-iothalamate clearance; TKV, by magnetic resonance imaging; biomarker excretion, by enzyme-linked immunosorbent assay; and osmolality, by freezing point depression.

RESULTS

In 27 participants (52% men; aged 46±10 years; mGFR, 69±39mL/min; TKV, 2.15 [IQR, 1.10-2.77] L), treatment with tolvaptan led to an increase in urine volume and free-water clearance and a decrease in urine osmolality, TKV, and kidney injury marker excretion. Changes in urine volume and osmolality with treatment were less in participants with lower baseline mGFRs (both P<0.01). However, change in fractional free-water clearance was greater at lower baseline mGFRs (P=0.001), suggesting that participants with decreased GFRs responded more to tolvaptan per functioning nephron.

LIMITATIONS

Limited sample size, no control group.

CONCLUSIONS

In patients with ADPKD with decreased kidney function, response to tolvaptan is lower for TKV, urinary volume, and osmolality, but larger for fractional free-water clearance. This latter finding suggests that patients with ADPKD with lower GFRs might benefit from long-term treatment with tolvaptan, as has been observed for patients with preserved GFRs.