Renal endpoints in renal and cardiovascular randomized clinical trials: time for a consensus?

Range and Heterogeneity of Outcomes in Randomized Trials of Pediatric Chronic Kidney Disease

OBJECTIVE

To determine the range and heterogeneity of outcomes reported in randomized controlled trials of interventions for children with chronic kidney disease (CKD).

STUDY DESIGN

The Cochrane Kidney and Transplant Specialized Register was searched to March 2016. Randomized trials involving children across all stages of CKD were selected. All outcome domains and measurements were extracted from included trials. The frequency and characteristics of the outcome domains and measures were evaluated.

RESULTS

From 205 trials included, 6158 different measurements of 100 different outcome domains were reported, with a median of 22 domains per trial (IQR 13-41). Overall, 52 domains (52%) were surrogate, 38 (38%) were clinical, and 10 (10%) were patient-reported. The 5 most commonly reported domains were blood pressure (76 [37%] trials), relapse/remission (70 [34%]), kidney function (66 [32%]), infection (61 [30%]), and height/pubertal development (51 [25%]). Mortality (14%), cardiovascular disease (4%), and quality of life (1%) were reported infrequently. The 2 most frequently reported outcomes, blood pressure and relapse/remission, had 56 and 81 different outcome measures, respectively.

CONCLUSIONS

The outcomes reported in clinical trials involving children with CKD are extremely heterogeneous and are most often surrogate outcomes, rather than clinical and patient-centered outcomes such as cardiovascular disease and quality of life. Efforts to ensure consistent reporting of outcomes that are important to patients and clinicians will improve the value of trials to guide clinical decision-making. In our study, non-English articles were excluded.

Doing it hard in the bush: Aligning what gets measured with what matters

What gets measured gets managed. Funding of health services is substantially determined by operational activity and specific outcome indicators. In day-to-day clinical decision-making, surrogate markers, such as glycosylated haemoglobin and blood pressure, are commonly used to modify risks of 'hard' outcomes that include kidney failure, ischaemic cardiac events, stroke and all-cause mortality. In many settings, surrogates are all we have to go on. As a consequence, current health funding models heavily rely on surrogate-based key performance indicators [KPIs]. While surrogates are convenient and provide immediate information, there is an obligation to ensure that they are appropriate, reliable and validated in context. In contrast, hard outcomes, the real consequences of illness, are usually realised over an extended timeframe. Additionally, and for a host of reasons, hard endpoints have the greatest social, emotional and economic impact for people at the far end of the health system; those in rural and remote settings - 'in the bush' - especially Indigenous Australians. We propose a health service assessment approach that aligns short-term decision-making with patient-centred and longer term hard outcomes, one that takes into account community, cultural and environmental factors, especially remoteness. Communities should have a major say in determining what health indicators are measured and managed.

The use of surrogate endpoints in regulating medicines for cardio-renal disease: opinions of stakeholders

Aim

There is discussion whether medicines can be authorized on the market based on evidence from surrogate endpoints. We assessed opinions of different stakeholders on this topic.

Methods

We conducted an online questionnaire that targeted various stakeholder groups (regulatory agencies, pharmaceutical industry, academia, relevant public sector organisations) and medical specialties (cardiology or nephrology vs. other). Participants were enrolled through purposeful sampling. We inquired for conditions under which surrogate endpoints can be used, the validity of various cardio-renal biomarkers and new approaches for biomarker use.

Results

Participants agreed that surrogate endpoints can be used when the surrogate is scientifically valid (5-point Likert response format, mean score: 4.3, SD: 0.9) or when there is an unmet clinical need (mean score: 3.8, SD: 1.2). Industry participants agreed to a greater extent than regulators and academics. However, out of four proposed surrogates (blood pressure (BP), HbA1c, albuminuria, CRP) for cardiovascular outcomes or end-stage renal disease, only use of BP for cardiovascular outcomes was deemed moderately accurate (mean: 3.6, SD: 1.1). Specialists in cardiology or nephrology tended to be more positive about the use of surrogate endpoints.

Conclusion

Stakeholders in drug development do not oppose to the use of surrogate endpoints in drug marketing authorization, but most surrogates are not considered valid. To solve this impasse, increased efforts are required to validate surrogate endpoints and to explore alternative ways to use them.

Peroxisome proliferator-activated receptor agonists in a battle against the aging kidney

As aging is a complex phenomenon characterized by intraindividual and interindividual diversities in the maintenance of the homeostatic condition of cells and tissues, changes in renal function are not uniform and depend on associated diseases and environmental factors. Multiple studies have investigated the possible underlying mechanisms of age-related decline in kidney function. Evolutionary, molecular, cellular and systemic theories have been postulated to explain the primary disease independent age-related changes and adaptive responses. As peroxisome proliferator-activated receptors (PPARs) are involved in a broad spectrum of biological processes, PPAR activation might have an effect on the prevention of cell senescence. In this review, we will focus on the experimental and clinical evidence of PPAR agonists in a battle against the aging kidney.

The emerging concept of chronic kidney disease without clinical proteinuria in diabetic patients

The natural history of diabetic nephropathy was defined in the 1980s on the basis of longitudinal studies undertaken in patients with type 1 and type 2 diabetes. However, an increasing number of studies have indicated that certain diabetic patients do not present with the same evolution as was then defined: for example, some often have significant initial deterioration of glomerular filtration rate whereas, in others, microalbuminuria is reduced spontaneously. Chronic kidney disease (CKD) may be accompanied, rather than preceded, by macroalbuminuria, or it may develop in patients with microalbuminuria or even in those with albuminuria levels that revert to normal. CKD can also develop in patients whose albuminuria levels remain normal. Progression to macroalbuminuria is, in fact, less frequent than regression to normoalbuminuria or no change in microalbuminuria status in diabetic patients with microalbuminuria, especially in type 1 diabetes. Some experience progressive deterioration of renal function due to diabetes without developing significant proteinuria: this is seen fairly frequently and can affect 50% of patients with renal insufficiency. Such cases are more often older patients treated with renin-angiotensin system blockers who usually have a history of cardiovascular disease. Evolution to end-stage renal disease is slower in this subgroup of patients, although histological analyses may show surprisingly advanced glomerular lesions. The main parameters of surveillance remain regular monitoring of glycaemia, and control of blood pressure and the evolution of initial albuminuria levels. Nevertheless, why some patients exhibit conventional diabetic nephropathy while others have slower declines in renal function associated with normal albuminuria levels or microalbuminuria is unclear. It is hoped that the new pathological classification of diabetic nephropathy will help in our understanding of these discrepancies.