Real-world costs of autosomal dominant polycystic kidney disease in the Nordics

Scoping Review of Economic Analyses of Rare Kidney Diseases

Introduction

Rare kidney diseases (RKDs) place a substantial economic burden on patients and health systems, the extent of which is unknown and may be systematically underestimated by health economic techniques. We aimed to investigate the economic burden and cost-effectiveness evidence base for RKDs.

Methods

We conducted a systematic scoping review to identify economic evaluations, health technology assessments, and cost-of-illness studies relating to RKDs, published since 2012.

Results

A total of 161 published studies, including 66 cost-of-illness studies and 95 economic evaluations; 72 grey literature reports were also included. Most published literature originated from high-income nations, particularly the USA (81 studies), and focused on a handful of diseases, notably renal cell carcinomas (70) and systemic lupus erythematosus (36). Limited evidence was identified from lower-income settings and there were few studies of genetic conditions, which make up most RKDs. Some studies demonstrated the cost-effectiveness of existing treatments; however, there were limited considerations of broader economic impacts on patients that may be important to those with RKDs. Included health technology assessments highlighted difficulties in obtaining high-quality clinical evidence for treatments in very small patient populations, and often considered equity issues and other patient impacts qualitatively alongside clinical and economic evidence in their recommendations.

Conclusion

We found large gaps in the economic evidence base for RKDs and limited adaptation of methods to account for the uniqueness of these diseases. There may be significant scope for innovation in building an investment case for RKD treatments, as well as in decision-making processes to inform investment decisions.

Healthcare costs in relation to kidney function among older people: the SCOPE study

PURPOSE

In this study, a comprehensive analysis of costs of chronic kidney disease (CKD) was performed, to understand factors associated with the economic burden of the disease in a multicentre international framework.

METHODS

The impact on costs of demographics, socio-economics, clinical, and functional variables was tested in 2204 subjects aged 75 years or more attending outpatient clinics in Europe using a multicentre 2-year prospective cohort study. By means of collected resources consumption and unit cost data a comprehensive cost database was built and then investigated using multilevel regression modeling.

RESULTS

Overall, hospitalization, medications and specialist visits were the main cost items, with a notable variability among countries. Estimated yearly costs were 4478€ ± 9804€, rising up to 6683€ ± 10,953€ for subjects with estimated Glomerular Filtration Rate (eGFR) < 30. Costs increased significantly according to the severity of the disease, gender and age. Clinical and functional covariates were also significantly associated with CKD-related total costs, even after correcting for the inter-country variability.

CONCLUSION

Findings corroborate the importance of multidimensional assessment of participants with CKD, as multimorbidity and functional disability produce a detrimental impact on participant's prognosis and cost of care. Preservation of functional impairment and adequate management of comorbidities may thus help decreasing the overall consumption on health care resources in CKD patients, especially in older people.

A cost-effectiveness analysis of RefluxStop against relevant therapeutic alternatives for chronic gastroesophageal reflux disease in Sweden

INTRODUCTION

The standard treatment for gastroesophageal reflux disease (GERD) is proton pump inhibitors (PPIs). In selected cases, Nissen fundoplication is offered as a surgical treatment option, but alternative endoscopic and minimally invasive surgical alternatives are emerging. RefluxStop is a new technology for the treatment of GERD.

RESEARCH DESIGN AND METHODS

A cost-effectiveness analysis of RefluxStop in comparison to PPI therapy and Nissen fundoplication in the Swedish healthcare setting was conducted using a Markov model and available comprehensive population and clinical trial-based long-term data. Benefits were measured in quality-adjusted life-years (QALYs). Uncertainty was determined by deterministic and probabilistic sensitivity analyses.

RESULTS

The base case incremental cost-effectiveness ratios (ICERs) for RefluxStop in comparison to PPIs and Nissen fundoplications were SEK 48,152 (€ 4,531) and SEK 62,966 (€ 5,925) per QALY gained, respectively. At a cost-effectiveness threshold of SEK 500,000 per QALY gained, RefluxStop has a high likelihood of being cost-effective, with probabilities of 96% and 100% against Nissen fundoplication and PPIs, respectively. The results of the model remained robust with sensitivity analysis.

CONCLUSIONS

RefluxStop may offer a highly cost-effective long-term treatment alternative for chronic GERD patients over lifelong PPI therapy, but also in comparison with laparoscopic Nissen fundoplication.

Cost-effectiveness of sodium zirconium cyclosilicate for the treatment of hyperkalemia in patients with chronic kidney disease or heart failure in Spain

BACKGROUND AND OBJECTIVE

Hyperkalemia (HK) is an electrolyte disturbance in the concentration of potassium ions (K+), whose risk increases in patients with chronic kidney disease (CKD) or heart failure (HF) and/or in patients being treated with renin-angiotensin-aldosterone system inhibitors (RAASi). The new oral K+ chelators offer a safe and effective treatment to maintain normokalemia in these patients. The objective of the analysis is to estimate the cost-effectiveness of sodium zirconium cyclosilicate (SZC) for the treatment of chronic HK in patients with CKD or HF versus standard treatment (calcium polystyrene sulfonate and lifestyle modifications) from the perspective of the Spanish National Health System.

MATERIALS AND METHODS

Two microsimulation models reflecting the natural history of CKD and HF were used. In both models, K+ levels were simulated individually. Based on efficacy (reduction of K+ levels), quality of life of patients (utilities according to health states, and disutilities of events derived from each pathology and adverse events [AEs] of treatment) and costs considered (cost of treatment for HK, of RAASi treatment and its modification, health states, management of events derived from each pathology, HK episodes, and AEs treatment) (, 2022), clinical benefit (quality-adjusted life years [QALYs]) and cost results were obtained. A time horizon of the patient's lifetime was used and a discount rate of 3% was applied for costs and outcomes.

RESULTS

SZC is a more effective option in both pathologies, with a difference in QALYs of 0.476 in CKD and 0.978 in HF compared to standard treatment, and it represents an incremental cost of 3,616 and 14,749, respectively, obtaining an incremental cost-utility ratio of 7,605/QALY in CKD and 15,078/QALY in HF.

CONCLUSIONS

SZC is a cost-effective alternative for the treatment of HK in patients with CKD or HF, taking into account the reference efficiency values commonly used in Spain.

Are We Capturing the Socioeconomic Burden of Rare Genetic Disease? A Scoping Review of Economic Evaluations and Cost-of-Illness Studies

BACKGROUND AND OBJECTIVES

Rare diseases have a significant impact on patients, families, the health system, and society. Measuring the socioeconomic burden is crucial to valuing interventions for rare diseases. Healthcare system costs are significant, but so are costs to other government sectors, patients, families, and society. To understand the breadth of costs captured in rare disease studies, we examined the cost categories and elements of socioeconomic burden captured in published studies.

METHODS

A scoping review was conducted using five electronic databases to identify English language economic evaluations and cost-of-illness studies of interventions for rare diseases (2011-21). We mapped costs using a previously developed evidence-informed framework of socioeconomic burden costs for rare disease.

RESULTS

Of 4890 studies identified, 48 economic evaluations and 22 cost-of-illness studies were included. While 18/22 cost-of-illness studies utilized a societal perspective, only 7/48 economic evaluations incorporated societal costs. Most reported cost categories related to medical costs, with medication and hospitalizations being the most common elements for both study designs. Costs borne by patients, families, and society were reported less among economic evaluations than cost-of-illness studies. These included: productivity (10% vs 77%), travel/accommodation (6% vs 68%), government benefits (4% vs 18%), and family impacts (0% vs 50%).

CONCLUSIONS

Contrary to cost-of-illness analyses, most of the included economic evaluations did not account for the hidden burden of rare diseases, that is, costs borne by patients, families, and societies. Including these types of costs in future studies would provide a more comprehensive picture of the burden of disease, providing empirical data to inform how we value and make decisions regarding rare disease interventions, health policy, and resource allocation.

Economic impact of the use of patiromer in chronic kidney disease or heart failure for the treatment of chronic hyperkalemia in Spain

INTRODUCTION

Chronic hyperkalemia has negative consequences in the medium and long term, and determines the suspension of nephro and cardioprotective drugs, such as renin-angiotensin-aldosterone system inhibitors (RAASi). There is an alternative to the suspension or dose reduction of these treatments: the administration of potassium chelators. The aim of this study is to estimate the economic impact of the use of patiromer in patients with chronic kidney disease (CKD) or heart failure (HF) and hyperkalemia in Spain.

MATERIALS AND METHOD

The annual economic impact of the use of patiromer has been estimated from the perspective of the Spanish society. Two scenarios were compared: patients with CKD or HF and hyperkalemia treated with and without patiromer. The costs have been updated to 2020 euros, using the Health Consumer Price Index. Direct healthcare costs related to the use of resources (treatment with RAASi, CKD progression, cardiovascular events and hospitalization due to hyperkalemia), direct non-healthcare costs (informal care: costs derived from time dedicated by patient's relatives), the indirect costs (productivity loss), as well as an intangible cost (due to premature mortality) were considered. A deterministic sensitivity analysis was performed to validate the robustness of the study results.

RESULTS

The mean annual cost per patient in the scenario without patiromer is €9,834.09 and €10,739.37 in CKD and HF, respectively. The use of patiromer would lead to cost savings of over 30% in both diseases. The greatest savings in CKD come from the delay in the progression of CKD. While in the case of HF, 80.1% of these savings come from premature mortality reduction. The sensitivity analyses carried out show the robustness of the results, obtaining savings in all cases.

CONCLUSIONS

The incorporation of patiromer allows better control of hyperkalemia and, as a consequence, maintain treatment with RAASi in patients with CKD or HF. This would generate a 32% of annual savings in Spain (€3,127 in CKD; €3,466 in HF). The results support the positive contribution of patiromer to health cost in patients with only CKD or in patients with only HF.

Autosomal dominant polycystic kidney disease in Colombia

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD) is the most common genetic cause of chronic kidney disease (CKD) that requires dialysis. Knowing geographical clusters can be critical for early diagnosis, progression control, and genetic counseling. The objective was to establish the prevalence, geographic location, and ethnic groups of patients with ADPKD who underwent dialysis or kidney transplant in Colombia between 2015 and 2019.

METHODS

We did a cross-sectional study with data from the National Registry of Chronic Kidney Disease (NRCKD) managed by the High-Cost Diseases Fund (Cuenta de Alto Costo [CAC] in Spanish) between July 1, 2015, and June 30, 2019. We included Colombian population with CKD with or without renal replacement therapy (RRT) due to ADPKD. Crude and adjusted prevalence rates were estimated by state and city.

RESULTS

3,339 patients with ADPKD were included, period prevalence was 9.81 per 100,000 population; there were 4.35 cases of RRT per 100,000 population, mean age of 52.58 years (± 13.21), and 52.78% women. Seventy-six patients were Afro-Colombians, six were indigenous, and one Roma people. A total of 46.07% began scheduled dialysis. The highest adjusted prevalence rate was in Valle del Cauca (6.55 cases per 100,000 population), followed by Risaralda, and La Guajira. Regarding cities, Cali had the highest prevalence rate (9.38 cases per 100,000 population), followed by Pasto, Medellin, and Bucaramanga.

CONCLUSIONS

ADPKD prevalence is lower compared to Europe and US; some states with higher prevalence could be objective to genetic prevalence study.

Cost effectiveness of sodium zirconium cyclosilicate for the treatment of hyperkalaemia in patients with CKD in Norway and Sweden

Background

Hyperkalaemia is common in patients with chronic kidney disease (CKD) and is associated with a range of adverse outcomes. Historically, options for management of chronic hyperkalaemia in the outpatient setting have been limited. Novel oral potassium binders provide a safe, effective therapy for maintenance of normokalaemia in patients with CKD, but despite being approved for reimbursement in many countries, prescription data indicate uptake has been slower than anticipated. This analysis aimed to demonstrate the value to patients and the healthcare system of the potassium binder sodium zirconium cyclosilicate (SZC) for treatment of hyperkalaemia in patients with CKD in Norway and Sweden.

Methods

A published simulation model reflecting the natural history of CKD was adapted to the Norwegian and Swedish settings and used to predict long-term health economic outcomes of treating hyperkalaemia with SZC versus usual care.

Results

SZC was highly cost effective compared to usual care in Norway and Sweden, with incremental cost-effectiveness ratios of €14,838/QALY in Norway and €14,352/QALY in Sweden, over a lifetime horizon. The acquisition cost of SZC was largely offset by cost savings associated with reductions in hyperkalaemia events and hospitalisations; a modest overall increase in costs was predominantly attributable to costs associated with gains in life years compared with usual care. SZC remained cost effective in all scenarios examined.

Conclusions

SZC was estimated to be cost effective for treating hyperkalaemia. Consequently, improving access to a clinically effective, safe and cost-effective therapy, such as SZC, may result in considerable benefits for CKD patients with hyperkalaemia.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-022-02903-7.

Investigation of presenteeism, physical function, and exercise habits in workers with CKD: three case reports with literature review

Management of presenteeism in the context of chronic kidney disease (CKD) is essential for disease management, ensuring the workforce's availability, and reducing health-related costs. The purpose of this case study was to investigate presenteeism, physical function, and exercise habits in three working patients with CKD and discuss their effects. Case 1 was a 71-year-old male security guard; Case 2 was a 72-year-old male agricultural worker; and Case 3 was an 83-year-old male civil engineering employee. Presenteeism was measured using the work functioning impairment scale (WFun), and physical function was measured using grip strength, skeletal muscle mass index, 10 m walk test, short physical performance battery, and exercise habits. The WFun assessment showed that only Case 3 had moderate presenteeism, and the barrier to employment was fatigue. Each value of physical function was higher than the reference value, but Case 3 had the lowest physical function values. All three patients had no exercise habits and were in the interest stage of behavior change. This case report indicates the existence of workers with CKD who need care for presenteeism, even if they have no problems with physical function or activities of daily living. To ensure work productivity in workers with CKD, clinicians may need to evaluate presenteeism, physical function, and exercise habits in addition to popular treatment and care.

Patient, family and productivity costs of end-stage renal disease in the Netherlands; exposing non-healthcare related costs

Background

Healthcare costs related to ESRD are well-described, but broader societal costs of ESRD are less known. This study aimed to estimate patient and family costs, including informal care costs and out-of-pocket costs, and costs due to productivity loss related to ESRD, for patients receiving dialysis and living with a kidney transplant, using a bottom-up approach.

Methods

A total of 655 patients were asked to complete a digital questionnaire consisting of two standardised instruments (iMCQ and iPCQ) from November 2016 through January 2017. We applied a retrospective bottom-up cost estimation by combining data from the questionnaire with unit prices from the Dutch costing manual.

Results

Our study sample consisted of 230 patients, of which 165 were kidney transplant recipients and 65 received dialysis. The total annual non-healthcare related costs were estimated at €8284 (SD: €14,266) for transplant recipients and €23,488 (SD: €39,434) for dialysis patients. Costs due to productivity loss contributed most to the total non-healthcare costs (66% for transplant recipients and 65% for dialysis patients), followed by informal care costs (26% resp. 29%) and out-of-pocket costs, such as medication and travel expenses (8% resp. 6%).

Conclusion

By exposing patient, family and productivity costs, our study revealed that dialysis and transplantation are not only costly within the healthcare system, but also incur high non-healthcare costs (18–23% resp. 35% of the total societal costs). It is important to reveal these types of non-healthcare costs in order to understand the full burden of ESRD for society and the potential impact of new therapies.

Cost-of-illness studies in rare diseases: a scoping review

OBJECTIVE

The aim of this scoping review was to overview the cost-of-illness studies conducted in rare diseases.

METHODS

We searched papers published in English in PubMed from January 2007 to December 2018. We selected cost-of-illness studies on rare diseases defined as those with prevalence lower than 5 per 10,000 cases. Studies were selected by one researcher and verified by a second researcher. Methodological characteristics were extracted to develop a narrative synthesis.

RESULTS

We included 63 cost-of-illness studies on 42 rare diseases conducted in 25 countries, and 9 systematic reviews. Most studies (94%) adopted a prevalence-based estimation, where the predominant design was cross-sectional with a bottom-up approach. Only four studies adopted an incidence-based estimation. Most studies used questionnaires to patients or caregivers to collect resource utilisation data (67%) although an important number of studies used databases or registries as a source of data (48%). Costs of lost productivity, non-medical costs and informal care costs were included in 68%, 60% and 43% of studies, respectively.

CONCLUSION

This review found a paucity of cost-of-illness studies in rare diseases. However, the analysis shows that the cost-of-illness studies of rare diseases are feasible, although the main issue is the lack of primary and/or aggregated data that often prevents a reliable estimation of the economic burden.

Cost-of-illness studies in rare diseases: a scoping review

OBJECTIVE

The aim of this scoping review was to overview the cost-of-illness studies conducted in rare diseases.

METHODS

We searched papers published in English in PubMed from January 2007 to December 2018. We selected cost-of-illness studies on rare diseases defined as those with prevalence lower than 5 per 10,000 cases. Studies were selected by one researcher and verified by a second researcher. Methodological characteristics were extracted to develop a narrative synthesis.

RESULTS

We included 63 cost-of-illness studies on 42 rare diseases conducted in 25 countries, and 9 systematic reviews. Most studies (94%) adopted a prevalence-based estimation, where the predominant design was cross-sectional with a bottom-up approach. Only four studies adopted an incidence-based estimation. Most studies used questionnaires to patients or caregivers to collect resource utilisation data (67%) although an important number of studies used databases or registries as a source of data (48%). Costs of lost productivity, non-medical costs and informal care costs were included in 68%, 60% and 43% of studies, respectively.

CONCLUSION

This review found a paucity of cost-of-illness studies in rare diseases. However, the analysis shows that the cost-of-illness studies of rare diseases are feasible, although the main issue is the lack of primary and/or aggregated data that often prevents a reliable estimation of the economic burden.

Investigation on the association between diabetes distress and productivity among patients with uncontrolled type 2 diabetes mellitus in the primary healthcare institutions

AIMS

To investigate associations between diabetes distress and productivity, and to identify the potential risk factors that could affect these particular associations.

METHODS

This cross-sectional study was conducted in three outpatient healthcare institutions. Patients aged ≥21 years with uncontrolled T2DM and polypharmacy were included. The Problem Areas in Diabetes (PAID) measuring diabetes distress and Work Productivity and Activity Impairment General Health (WPAI-GH) measuring productivity were administered by trained interviewers.

RESULTS

A total of 259 patients were analysed. Point prevalence of clinically severe diabetes distress, work productivity loss and life productivity loss were 7.7%, 45.0% and 35.1% respectively. Diabetes distress was positively associated with work productivity loss (p = 0.001) and life productivity loss (p < 0.001). Multiple linear regression analysis demonstrated that diabetes distress (p = 0.003), the total number of chronic medications (p = 0.012), insulin therapy (p = 0.027) and the presence of chronic kidney disease (p = 0.038) were significantly associated with work impairment. Diabetes distress (p = 0.001) and the presences of osteoarthritis (p = 0.039) were significantly associated with activity impairment.

CONCLUSION

Healthcare professionals should screen patients for diabetes distress to prevent productivity losses, especially in patients with polypharmacy and/or on insulin and with coexisting osteoarthritis or chronic kidney disease.

Advances in our understanding of genetic kidney disease using kidney organoids

A significant proportion of kidney disease presenting in childhood is likely genetic in origin with a growing number of genes implicated in its development. However, many children may have changes in previously undescribed or unrecognised genes. The recent development of methods for generating human kidney organoids from human pluripotent stem cells has the potential to substantially change the rate of diagnosis and the development of new treatments for some forms of genetic kidney disease. In this review, we discuss how accurately a kidney organoid models the human kidney, identifying the strengths and weaknesses of these potentially patient-derived models of renal disease.

The impact of chronic kidney disease on developed countries from a health economics perspective: A systematic scoping review

Chronic kidney disease (CKD) affects over 10% of the global population and poses significant challenges for societies and health care systems worldwide. To illustrate these challenges and inform cost-effectiveness analyses, we undertook a comprehensive systematic scoping review that explored costs, health-related quality of life (HRQoL) and life expectancy (LE) amongst individuals with CKD. Costs were examined from a health system and societal perspective, and HRQoL was assessed from a societal and patient perspective. Papers published in English from 2015 onward found through a systematic search strategy formed the basis of the review. All costs were adjusted for inflation and expressed in US$ after correcting for purchasing power parity. From the health system perspective, progression from CKD stages 1-2 to CKD stages 3a-3b was associated with a 1.1-1.7 fold increase in per patient mean annual health care cost. The progression from CKD stage 3 to CKD stages 4-5 was associated with a 1.3-4.2 fold increase in costs, with the highest costs associated with end-stage renal disease at $20,110 to $100,593 per patient. Mean EuroQol-5D index scores ranged from 0.80 to 0.86 for CKD stages 1-3, and decreased to 0.73-0.79 for CKD stages 4-5. For treatment with renal replacement therapy, transplant recipients incurred lower costs and demonstrated higher HRQoL scores with longer LE compared to dialysis patients. The study has provided a comprehensive updated overview of the burden associated with different CKD stages and renal replacement therapy modalities across developed countries. These data will be useful for the assessment of new renal services/therapies in terms of cost-effectiveness.

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.

European ADPKD Forum multidisciplinary position statement on autosomal dominant polycystic kidney disease care: European ADPKD Forum and Multispecialist Roundtable participants

Autosomal dominant polycystic kidney disease (ADPKD) is a chronic, progressive condition characterized by the development and growth of cysts in the kidneys and other organs and by additional systemic manifestations. Individuals with ADPKD should have access to lifelong, multidisciplinary, specialist and patient-centred care involving: (i) a holistic and comprehensive assessment of the manifestations, complications, prognosis and impact of the disease (in physical, psychological and social terms) on the patient and their family; (ii) access to treatment to relieve symptoms, manage complications, preserve kidney function, lower the risk of cardiovascular disease and maintain quality of life; and (iii) information and support to help patients and their families act as fully informed and active partners in care, i.e. to maintain self-management approaches, deal with the impact of the condition and participate in decision-making regarding healthcare policies, services and research. Building on discussions at an international roundtable of specialists and patient advocates involved in ADPKD care, this article sets out (i) the principles for a patient-centred, holistic approach to the organization and delivery of ADPKD care in practice, with a focus on multispecialist collaboration and shared-decision making, and (ii) the rationale and knowledge base for a route map for ADPKD care intended to help patients navigate the services available to them and to help stakeholders and decision-makers take practical steps to ensure that all patients with ADPKD can access the comprehensive multispecialist care to which they are entitled. Further multispecialty collaboration is encouraged to design and implement these services, and to work with patient organizations to promote awareness building, education and research.

Modelling the long-term benefits of tolvaptan therapy on renal function decline in autosomal dominant polycystic kidney disease: an exploratory analysis using the ADPKD outcomes model

Background

The short-term efficacy of tolvaptan in patients with autosomal dominant polycystic kidney disease (ADPKD) has been demonstrated across several phase 3 trials, while the ADPKD Outcomes Model (ADPKD-OM) represents a validated approach to predict natural disease progression over a lifetime horizon. This study describes the implementation of a tolvaptan treatment effect within the ADPKD-OM and explores the potential long-term benefits of tolvaptan therapy in ADPKD.

Methods

The effect of tolvaptan on ADPKD progression was modelled by applying a constant treatment effect to the rate of renal function decline, consistent with that observed in the Tolvaptan Efficacy and Safety in Management of Autosomal Dominant Polycystic Kidney Disease and Its Outcomes trial (TEMPO 3:4; ClinicalTrials.gov identifier NCT00428948). Predictions generated by the ADPKD-OM were compared against aggregated data from a subsequent extension trial (TEMPO 4:4; ClinicalTrials.gov identifier NCT01214421) and the Replicating Evidence of Preserved Renal Function an Investigation of Tolvaptan Safety Efficacy in ADPKD trial (REPRISE; ClinicalTrials.gov identifier NCT02160145). Following validation, an application of the ADPKD-OM sought to estimate the benefit of tolvaptan therapy on time to end-stage renal disease (ESRD), in a range of ADPKD populations.

Results

Model validation against TEMPO 4:4 and REPRISE demonstrated the accuracy and generalisability of the tolvaptan treatment effect applied within the ADPKD-OM. In simulated patients matched to the overall TEMPO 3:4 trial population at baseline, tolvaptan therapy was predicted to delay the mean age of ESRD onset by five years, compared to natural disease progression (57 years versus 52 years, respectively). In subgroup and sensitivity analyses, the estimated delay to ESRD was greatest among patients with CKD stage 1 at baseline (6.6 years), compared to CKD 2 and 3 subgroups (4.7 and 2.7 years, respectively); and ADPKD patients in Mayo subclasses 1C–1E.

Conclusions

This study demonstrated the potential for tolvaptan therapy to delay time to ESRD, particularly among patients with early-stage CKD and evidence of rapidly progressing disease. Data arising from this study highlight the value to be gained by early intervention and long-term treatment with tolvaptan, which may alleviate the economic and societal costs of providing care to patients who progress to ESRD.