Range and Variability of Outcomes Reported in Randomized Trials Conducted in Patients With Polycystic Kidney Disease: A Systematic Review

Validating the SONG-PKD Pain Instrument, a Core Outcome Measure for Pain in ADPKD

Introduction

Pain is a critically important outcome in autosomal dominant polycystic kidney disease (ADPKD); however, it is infrequently and inconsistently reported in clinical trials. This study aimed to validate the Standardized Outcomes in Nephrology-Polycystic Kidney Disease (SONG-PKD) Pain measure, which includes 3 items related to pain (frequency, severity, and impact on life participation) measured on a 5-point Likert scale, in adults with ADPKD.

Methods

A total of 316 adults with ADPKD from 21 countries participated online. The median (interquartile range) age of participants was 56 (44-66) years, 219 (69%) were female, and 222 (70%) had a university degree or higher. Participants completed a demographic questionnaire, brief medical history, and 4 pain measures at baseline. The pain measures were readministered 2 days later. Internal consistency was evaluated with Cronbach's alpha. Test-retest reliability was assessed using intraclass correlation coefficient (ICC), and convergent validity was assessed using Spearman's rho. Known groups comparisons for patients with or without a history of kidney complications were performed using a Mann-Whitney rank sum test.

Results

The SONG-PKD Pain measure demonstrated high internal consistency (0.94, 95% confidence interval [CI]: 0.93-0.95) and test-retest reliability (0.92, 95% CI: 0.90-0.94). There was a high convergence of SONG-PKD Pain with the Brief Pain Inventory-Short Form (BPI-SF; 0.84, 95% CI: 0.80-0.87) and a visual analog scale (VAS; 0.84, 95% CI: 0.81-0.87). There was a significant difference in the median scores of patients with and without a history of complications (4.0 vs. 0.0, P < 0.001).

Conclusion

SONG-PKD Pain instrument is a brief and simple measure that has demonstrated strong psychometric properties.

Outcomes for clinical trials involving adults with chronic kidney disease: a multinational Delphi survey involving patients, caregivers and health professionals

BACKGROUND

Many outcomes of high priority to patients and clinicians are infrequently and inconsistently reported across trials in chronic kidney disease (CKD), which generates research waste and limits evidence-informed decision making. We aimed to generate consensus among patients/caregivers and health professionals on critically important outcomes for trials in CKD prior to kidney failure and the need for kidney replacement therapy, and to describe the reasons for their choices.

METHODS

This was an online two-round international Delphi survey. Adult patients with CKD (all stages and diagnoses), caregivers and health professionals who could read English, Spanish or French were eligible. Participants rated the importance of outcomes using a Likert scale (7-9 indicating critical importance) and a Best-Worst Scale. The scores for the two groups were assessed to determine absolute and relative importance. Comments were analysed thematically.

RESULTS

In total, 1399 participants from 73 countries completed Round 1 of the Delphi survey, including 628 (45%) patients/caregivers and 771 (55%) health professionals. In Round 2, 790 participants (56% response rate) from 63 countries completed the survey including 383 (48%) patients/caregivers and 407 (52%) health professionals. The overall top five outcomes were: kidney function, need for dialysis/transplant, life participation, cardiovascular disease and death. In the final round, patients/caregivers indicated higher scores for most outcomes (17/22 outcomes), and health professionals gave higher priority to mortality, hospitalization and cardiovascular disease (mean difference >0.3). Consensus was based upon the two groups yielding median scores of ≥7 and mean scores >7, and the proportions of both groups rating the outcome as 'critically important' being >50%. Four themes reflected the reasons for their priorities: imminent threat of a health catastrophe, signifying diminishing capacities, ability to self-manage and cope, and tangible and direct consequences.

CONCLUSION

Across trials in CKD, the outcomes of highest priority to patients, caregivers and health professionals were kidney function, need for dialysis/transplant, life participation, cardiovascular disease and death.

Variability in Methodology of Erectile Dysfunction Regenerative Therapy Trials on ClinicalTrials.gov

OBJECTIVE

To evaluate the variability in the criteria of erectile dysfunction (ED) regenerative therapy trials registered on ClinicalTrials.gov.

METHODS

Interventional trials on ClinicalTrials.gov with the keywords "erectile dysfunction" and variations of "shockwave," "platelet rich plasma," "stem cell," "regenerative," and "restorative" were examined. Inclusion/exclusion criteria and primary/secondary outcomes were compared between extracorporeal shockwave therapy (ESWT), platelet rich plasma and stem cell injections (PRP/SC), and other regenerative therapies (ORT) groups.

RESULTS

Of the 92 trials analyzed, International Index of Erectile Function (IIEF) score was the most common primary outcome (72%), with a higher prevalence in ESWT trials than PRP/SC or ORT trials (89% vs 44% and 58%, P <.001). Safety/tolerability was a primary outcome for 44% of PRP/SC trials and 25% of ORT trials but no ESWT trials (P <.001). ESWT trials more frequently had sexual/romantic relationship-based inclusion criteria and cancer treatment-related exclusion criteria than PRP/SC and ORT trials.

CONCLUSION

There is substantial variability in the inclusion/exclusion criteria and outcome measures among ED regenerative therapy trials. ESWT trials most frequently utilized IIEF and had the strictest inclusion/exclusion criteria, suggesting more rigorous and functional outcome-based studies. Conversely, PRP/SC and ORT trials, but not ESWT trials, had safety/tolerability as a primary outcome, likely due to the experimental nature of these therapies. The variability in inclusion/exclusion criteria and outcome measures limits comparison of the various ED regenerative therapies.

Core Patient-Reported Outcomes for Trials in Nephrology

The outcomes reported in trials across all stages of chronic kidney disease (CKD) are highly variable and often do not include outcomes that are directly relevant to patients and caregivers. Frequently, the outcomes reported in trials are often unvalidated surrogate biochemical end points. The omission of outcomes that are meaningful and important to patients can diminish the value of trials in supporting treatment decisions. In response, there have been increasing efforts across many health and medical disciplines to develop core outcome sets, defined as the minimum set of outcomes to be reported in all trials in a specific health area to improve the relevance and consistency of reporting trial outcomes. The international Standardized Outcomes in Nephrology (SONG) initiative was established in 2014 and has since developed seven core outcome sets for different diagnosis and treatment stages of CKD. The core outcomes were based on consensus among patients, caregivers, and health professionals. Each core outcome set includes at least one patient-reported outcome, including fatigue (hemodialysis), life participation (kidney transplantation, peritoneal dialysis, early CKD not yet requiring kidney replacement therapy, children and adolescents, and glomerular disease), and pain (polycystic kidney disease). This article outlines how patient-reported outcomes are currently reported in trials, discusses core patient-reported outcomes that have been established for trials in kidney disease, and outlines strategies for implementing core patient-reported outcomes in trials.

Patient-Centered Research and Innovation in Nephrology

Patient involvement in research can improve the relevance of research, consequently enhancing the recruitment, retention, and uptake of interventions and policies impacting patient outcomes. Despite this, patients are not often involved in the design and conduct of research. The research agenda and innovations are frequently determined by the interest of health and industry professionals rather than proactively aligning with the priorities of patients. It is now being encouraged and recommended to engage patients in research priority setting to ensure interventions and trials report outcomes valuable to patients, moving away from a history of overlooking the outcomes that reflect the feel and function of patients. Involving patients ensures constant innovative research in nephrology, as this broader depth of evidence fortifies reliability and validity through knowledge gained from lived experience. Findings from such research can enhance clinical practice and strengthen decision-making and policy to support better outcomes. We aim to outline principles and strategies for patient involvement in research, including setting research priorities, identifying and designing interventions, selecting outcomes, and disseminating and translating research. Principles and strategies including engagement, education and training, empowerment, and connection and community provide guidance in patient involvement. There are increasing efforts to involve patients across all stages of research including setting research priorities. Efforts are rising to involve patients across all stages of research including priority setting, identifying and designing interventions, selecting outcomes, and dissemination and translation. Patient involvement throughout the research cycle drives innovative investigations ensuring funding, efforts, and resources are directed toward priorities of patients, contributing to catalyst advancements in care and outcomes.

Cardiovascular Manifestations and Management in ADPKD

Cardiovascular disease (CVD) is the major cause of mortality in autosomal dominant polycystic kidney disease (ADPKD) and contributes to significant burden of disease. The manifestations are varied, including left ventricular hypertrophy (LVH), intracranial aneurysms (ICAs), valvular heart disease, and cardiomyopathies; however, the most common presentation and a major modifiable risk factor is hypertension. The aim of this review is to detail the complex pathogenesis of hypertension and other extrarenal cardiac and vascular conditions in ADPKD drawing on preclinical, clinical, and epidemiological evidence. The main drivers of disease are the renin-angiotensin-aldosterone system (RAAS) and polycystin-related endothelial cell dysfunction, with the sympathetic nervous system (SNS), nitric oxide (NO), endothelin-1 (ET-1), and asymmetric dimethylarginine (ADMA) likely playing key roles in different disease stages. The reported rates of some manifestations, such as LVH, have decreased likely due to the use of antihypertensive therapies; and others, such as ischemic cardiomyopathy, have been reported with increased prevalence likely due to longer survival and higher rates of chronic disease. ADPKD-specific screening and management guidelines exist for hypertension, LVH, and ICAs; and these are described in this review.

The lonidamine derivative H2-gamendazole reduces cyst formation in polycystic kidney disease

Autosomal dominant polycystic kidney disease (ADPKD) is a debilitating renal neoplastic disorder with limited treatment options. It is characterized by the formation of large fluid-filled cysts that develop from kidney tubules through abnormal cell proliferation and cyst-filling fluid secretion driven by cAMP-dependent Cl- secretion. We tested the effectiveness of the indazole carboxylic acid H2-gamendazole (H2-GMZ), a derivative of lonidamine, to inhibit these processes using in vitro and in vivo models of ADPKD. H2-GMZ was effective in rapidly blocking forskolin-induced, Cl--mediated short-circuit currents in human ADPKD cells, and it significantly inhibited both cAMP- and epidermal growth factor-induced proliferation of ADPKD cells. Western blot analysis of H2-GMZ-treated ADPKD cells showed decreased phosphorylated ERK and decreased hyperphosphorylated retinoblastoma levels. H2-GMZ treatment also decreased ErbB2, Akt, and cyclin-dependent kinase 4, consistent with inhibition of heat shock protein 90, and it decreased levels of the cystic fibrosis transmembrane conductance regulator Cl- channel protein. H2-GMZ-treated ADPKD cultures contained a higher proportion of smaller cells with fewer and smaller lamellipodia and decreased cytoplasmic actin staining, and they were unable to accomplish wound closure even at low H2-GMZ concentrations, consistent with an alteration in the actin cytoskeleton and decreased cell motility. Experiments using mouse metanephric organ cultures showed that H2-GMZ inhibited cAMP-stimulated cyst growth and enlargement. In vivo, H2-GMZ was effective in slowing postnatal cyst formation and kidney enlargement in the Pkd1flox/flox: Pkhd1-Cre mouse model. Thus, H2-GMZ treatment decreases Cl- secretion, cell proliferation, cell motility, and cyst growth. These properties, along with its reported low toxicity, suggest that H2-GMZ might be an attractive candidate for treatment of ADPKD.NEW & NOTEWORTHY Autosomal dominant polycystic kidney disease (ADPKD) is a renal neoplastic disorder characterized by the formation of large fluid-filled cysts that develop from kidney tubules through abnormal cell proliferation and cyst-filling fluid secretion driven by cAMP-dependent Cl- secretion. This study shows that the lonidamine derivative H2-GMZ inhibits Cl- secretion, cell proliferation, and cyst growth, suggesting that it might have therapeutic value for the treatment of ADPKD.

A Systematic Review of Reported Outcomes in ADPKD Studies

Introduction

Methods

Results

Conclusion

Patient-centred clinical trial design

Patient involvement in clinical trial design can facilitate the recruitment and retention of participants as well as potentially increase the uptake of the tested intervention and the impact of the findings on patient outcomes. Despite these benefits, patients still have very limited involvement in designing and conducting trials in nephrology. Many trials do not address research questions and outcomes that are important to patients, including patient-reported outcomes that reflect how patients feel and function. This limitation can undermine the relevance, reliability and value of trial-based evidence for decision-making in clinical practice and health policy. However, efforts to involve patients with kidney disease are increasing across all stages of the trial process from priority setting, to study design (including selection of outcomes and approaches to improve participant recruitment and retention) and dissemination and implementation of the findings. Harnessing the patient voice in designing trials can ensure that efforts and resources are directed towards patient-centred trials that address the needs, concerns and priorities of patients living with kidney disease with the aim of achieving transformative improvements in care and outcomes.

Flank pain has a significant adverse impact on quality of life in ADPKD: the CYSTic-QoL study

Background

Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited kidney disorder and a major cause of kidney failure worldwide. However, its impact on quality-of-life has not been systematically explored.

Methods

The CYSTic-QoL study was an observational study designed to study quality-of-life in adult European ADPKD patients with an estimated glomerular filtration rate (eGFR) ≥30 mL/min/1.73 m². A total of 465 patients were recruited from six expert European centres with baseline data recorded, including health-related quality-of-life (HRQoL), incorporating a Kidney Disease QoL short form questionnaire (KDQoL-SF, version 1.3), magnetic resonance imaging (MRI) for total kidney volume (TKV) measurements and DNA for genotyping. The cohort was stratified by baseline eGFR, TKV or genotype and correlated with HRQoL scores. Bivariate and multivariate analyses were applied to examine the relationship between HRQoL and variables of interest. KDQoL-SF scores were calculated using an online tool provided by the RAND organization. For 36-item short form values, mean centre scores were normalized to their native populations.

Results

The mean age of participants was 43 years and 55% were female, with a mean eGFR of 77 mL/min/1.73 m² and height-adjusted TKV (ht-TKV) of 849 mL/min; 66% had PKD1 pathogenic variants. ADPKD patients uniformly reported decreased general health and less energy, with the majority also experiencing poorer physical, mental or emotional health and limitations in social functioning. A total of 32.5% of participants experienced flank pain, which was significantly and negatively correlated with the majority of KDQoL-SF subscales by multivariate analysis. Higher ht-TKV and lower eGFR were negatively associated with decreased energy and poorer physical health, respectively, although not with flank pain.

Conclusion

ADPKD patients suffer from significantly decreased QoL in multiple domains, exacerbated particularly by chronic pain.

A Core Outcome Set for Trials in Glomerular Disease: A Report of the Standardized Outcomes in Nephrology-Glomerular Disease (SONG-GD) Stakeholder Workshops

BACKGROUND AND OBJECTIVES

Outcomes reported in trials in adults with glomerular disease are often selected with minimal patient input, are heterogeneous, and may not be relevant for clinical decision making. The Standardized Outcomes in Nephrology-Glomerular Disease (SONG-GD) initiative aimed to establish a core outcome set to help ensure that outcomes of critical importance to patients, care partners, and clinicians are consistently reported.

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

We convened two 1.5-hour workshops in Melbourne, Australia, and Washington, DC, United States. Attendees were identified purposively with 50 patients/care partners and 88 health professionals from 19 countries; 51% were female. Patients and care partners were from the United States, Australia, and Canada, and had experience of a glomerular disease with systemic features (n=9), kidney-limited nephrotic disease (n=9), or other kidney-limited glomerular disease (n=8). Attendees reviewed the results of the SONG-GD Delphi survey and aims of the workshop and then discussed potential core outcomes and their implementation in trials among moderated breakout groups of eight to 12 people from diverse backgrounds. Transcripts of discussions were analyzed thematically.

RESULTS

Three themes were identified that supported the proposed core outcomes: limiting disease progression, stability and control, and ensuring universal relevance (i.e., applicable across diverse populations and settings). The fourth theme, preparedness for implementation, included engaging with funders and regulators, establishing reliable and validated measures, and leveraging existing endorsements for patient-reported outcomes.

CONCLUSIONS

Workshop themes demonstrated support for kidney function, disease activity, death, life participation, and cardiovascular disease, and these were established as the core outcomes for trials in adults with glomerular disease. Future work is needed to establish the core measures for each domain, with funders and regulators central to the uptake of the core outcome set in trials.

Standardised Outcomes in Nephrology - Chronic Kidney Disease (SONG-CKD): a protocol for establishing a core outcome set for adults with chronic kidney disease who do not require kidney replacement therapy

BACKGROUND

Globally, over 1.2 million people die from chronic kidney disease (CKD) every year. Patients with CKD are up to 10 times more likely to die prematurely than progress to kidney failure requiring kidney replacement therapy. The burden of symptoms and impaired quality of life in CKD may be compounded by comorbidities and treatment side effects. However, patient-important outcomes remain inconsistently and infrequently reported in trials in patients with CKD, which can limit evidence-informed decision-making. The Standardised Outcomes in Nephrology - Chronic Kidney Disease (SONG-CKD) aims to establish a consensus-based core outcome set for trials in patients with CKD not yet requiring kidney replacement therapy to ensure outcomes of relevance to patients, caregivers and health professionals are consistently reported in trials.

METHODS

SONG-CKD involves four phases: a systematic review to identify outcomes (domains and measures) that have been reported in randomised controlled trials involving adults with CKD who do not require kidney replacement therapy; stakeholder key informant interviews with health professionals involved in the care of adults with CKD to ascertain their views on establishing core outcomes in CKD; an international two-round online Delphi survey with patients, caregivers, clinicians, researchers, policy makers and industry representatives to obtain consensus on critically important outcome domains; and stakeholder consensus workshops to review and finalise the set of core outcome domains for trials in CKD.

DISCUSSION

Establishing a core outcome set to be reported in trials in patients with CKD will enhance the relevance, transparency and impact of research to improve the lives of people with CKD.

TRIAL REGISTRATION

Not applicable. This study is registered with the Core Outcome Measures in Effectiveness Trials (COMET) database: http://www.comet-initiative.org/Studies/Details/1653 .

Establishing a core outcome measure for pain in patients with autosomal dominant polycystic kidney disease: a consensus workshop report

Background

Pain is the highest prioritized patient-reported outcome in people with autosomal dominant polycystic kidney disease (ADPKD) but remains infrequently and inconsistently measured in clinical trials and poorly managed in clinical settings. A recently completed systematic review of pain in ADPKD identified 26 different outcome measures. None of these measures were considered appropriate as a core outcome measure due to the lack of patient-important dimensions, inadequate content, relatively long duration of completion time and limited evidence to support psychometric robustness.

Methods

We convened an international Standardized Outcomes in Nephrology–Polycystic Kidney Disease consensus workshop involving 21 patients/caregivers and 40 health professionals (clinicians, nurses, researchers, policy makers and industry representatives) from 18 countries to discuss the identification or development of a core outcome measure for pain.

Results

Four themes were identified highlighting fundamental issues for the measurement of pain in ADPKD: distressing and disrupting life participation; variability and ambiguity in defining pain; stigma, frustration and adaptation to pain; and ensuring validity and feasibility of pain measures.

Conclusions

Existing measures were found to be insufficient in capturing pain as a core outcome and there was consensus on the need for a new validated measure that is simple, succinct and addresses the impact of pain on life participation. This measure will facilitate the appropriate prioritization of pain in all trials and guide clinical decision making in people with ADPKD.

Patient-reported outcome measures for pain in autosomal dominant polycystic kidney disease: A systematic review

Pain is a common symptom in people with autosomal dominant polycystic kidney disease (ADPKD), but it is assessed and reported inconsistently in research, and the validity of the measures remain uncertain. The aim of this study was to identify the characteristics, content, and psychometric properties of measures for pain used in ADPKD. We conducted a systematic review including all trials and observational studies that reported pain in people with ADPKD. Items from all measures were categorized into content and measurement dimensions of pain. We assessed the general characteristics and psychometric properties of all measures. 118 studies, we identified 26 measures: 12 (46%) measures were developed for a non-ADPKD population, 1 (4%) for chronic kidney disease, 2 (8%) for polycystic liver disease and 11 (42%) specifically for ADPKD. Ten anatomical sites were included, with the lower back the most common (10 measures [39%]), four measurement dimensions (intensity (23 [88%]), frequency (3 [12%]), temporality (2 [8%]), and sensory (21 [81%]), two pain types, nociceptive including visceral (15 [58%]) and somatic (5 [20%]), and neuropathic (2 [8%]), and twelve impact dimensions, where the most frequent was work (5 [31%]). The validation data for the measures were variable and only the ADPKD Impact Scale reported all psychometric domains. The measures for pain in ADPKD varied in terms of content and length, and most had not been validated in ADPKD. A standardized psychometrically robust measure that captures patient-important dimensions of pain is needed to evaluate and manage this debilitating complication of ADPKD.

Variability in Human-Animal Interaction Research

The field of Human-Animal Interaction (HAI) is plagued with mixed results. Some findings appear to indicate that interacting with a companion animal is beneficial for some aspect of human health and well-being, while other research outcomes are inconclusive or even indicate the opposite. The purpose of this paper is to take a closer look at this variability in research outcomes and to provide plausible explanations and potential remedies. Some of the reasons for mixed results are likely due to the wide variety of methodologies implemented, intermittent use of standardized measures and manualized protocols, variability in human and animal participants, and limited quantification of human-animal interactions or definitions of pet ownership. Variability in research outcomes is not unique to HAI and is, in fact, not uncommon in many more established fields such as psychology and medicine. However, the potential reasons for the variability may be linked to the unique nature of HAI in that, in its' simplest form, it involves two complex organisms, a human and an animal, interacting in dynamic ways. We argue that this complexity makes research in this field particularly challenging and requires a broad spectrum of theoretical and methodological considerations to improve rigor while ensuring the validity and reliability of conclusions drawn from study results.

Establishing a Core Outcome Set for Autosomal Dominant Polycystic Kidney Disease: Report of the Standardized Outcomes in Nephrology-Polycystic Kidney Disease (SONG-PKD) Consensus Workshop

The omission of outcomes that are of relevance to patients, clinicians, and regulators across trials in autosomal dominant polycystic kidney disease (ADPKD) limits shared decision making. The Standardized Outcomes in Nephrology-Polycystic Kidney Disease (SONG-PKD) Initiative convened an international consensus workshop on October 25, 2018, to discuss the identification and implementation of a potential core outcome set for all ADPKD trials. This article summarizes the discussion from the workshops and the SONG-PKD core outcome set. Key stakeholders including 11 patients/caregivers and 47 health professionals (nephrologists, policy makers, industry, and researchers) attended the workshop. Four themes emerged: "Relevance of trajectory and impact of kidney function" included concerns about a patient's prognosis and uncertainty of when they may need to commence kidney replacement therapy and the lack of an early prognostic marker to inform long-term decisions; "Discerning and defining pain specific to ADPKD" highlighted the challenges in determining the origin of pain, adapting to the chronicity and repeated episodes of pain, the need to place emphasis on pain management, and to have a validated measure for pain; "Highlighting ADPKD consequences" encompassed cyst-related complications and reflected patient's knowledge because of family history and the hereditary nature of ADPKD; and "Risk for life-threatening but rare consequences" such as cerebral aneurysm meant considering both frequency and severity of the outcome. Kidney function, mortality, cardiovascular disease, and pain were established as the core outcomes for ADPKD.