Time-Varying Proteinuria and Progression of IgA Nephropathy: A Cohort Study

RATIONALE & OBJECTIVE

Proteinuria is a surrogate end point for predicting long-term kidney outcomes in IgA nephropathy (IgAN) with levels<1g/day identified as a therapeutic target. However, this threshold has not been sufficiently studied. We quantified the associations of progression of IgAN with various levels of proteinuria.

STUDY DESIGN

Observational cohort study.

SETTING & PARTICIPANTS

1,530 patients with IgAN and at least 12 months of follow-up at Peking University First Hospital.

EXPOSURE

Proteinuria levels updated over time (time-varying proteinuria, TVP).

OUTCOME

A composite kidney outcome of a 50% reduction in the estimated glomerular filtration rate or end-stage kidney disease.

ANALYTICAL APPROACH

Marginal structural models.

RESULTS

After a median follow-up period of 43.5 (IQR, 27.2-72.8) months, 254 patients (16.6%) developed the composite kidney outcome. A graded association was observed between TVP and composite kidney outcomes with higher risk among those with proteinuria of≥0.5g/day. Compared with TVP<0.3g/day, the HRs for proteinuria levels of 0.3 to<0.5g/day, 0.5 to<1.0g/day, 1.0 to<2.0g/day, and≥2.0g/day were 2.22 (95% CI, 0.88-5.58), 4.04 (95% CI, 1.93-8.46), 8.46 (95% CI, 3.80-18.83), and 38.00 (95% CI, 17.62-81.95), respectively. The trend was more pronounced in patients with baseline proteinuria of≥1.0g/day, among whom a higher risk was observed with TVP of 0.3 to<0.5g/day compared with TVP<0.3g/day (HR, 3.26 [95% CI, 1.07-9.92], P=0.04). However, in patients with baseline proteinuria levels of<1g/day, the risk of composite kidney outcome only began to increase when TVP was≥1.0g/day (HR, 3.25 [95% CI, 1.06-9.90]).

LIMITATIONS

Single-center observational study, selection bias, and unmeasured confounders.

CONCLUSIONS

This study showed that patients with IgAN and proteinuria levels of>0.5g/day, have an elevated risk of kidney failure especially among patients with proteinuria levels≥1.0g/day before initiating treatment. These data may serve to inform the selection of proteinuria targets in the treatment of IgAN.

PLAIN-LANGUAGE SUMMARY

The presence of proteinuria has often been considered a surrogate end point and a possible therapeutic target in clinical trials in IgA nephropathy (IgAN). Some guidelines recommend a reduction in proteinuria to<1g/day as a treatment goal based on the results of previous longitudinal studies. However, these findings may have been biased because they did not properly adjust for time-dependent confounders. Using marginal structural models to appropriately account for these confounding influences, we observed that patients with IgAN and proteinuria levels≥0.5g/day have an elevated risk of kidney failure, especially among patients who had proteinuria levels of≥1.0g/day before initiating treatment. These data may serve to inform the selection of proteinuria targets in the treatment of IgAN.

Intensive blood pressure control and the progression of IgA nephropathy: a cohort study using marginal structural models

BACKGROUND

In chronic kidney disease, current guidelines recommend systolic blood pressure (SBP) below 120 mmHg. However, the renoprotective effect of intensive blood-pressure (BP) lowering on immunoglobulin A nephropathy (IgAN) remains undetermined. We aimed to determine the effect of intensive BP control on the progression of IgAN.

METHODS

At Peking University First Hospital, 1530 patients with IgAN were enrolled. An examination of the relationship between baseline and time-updated BP and composite kidney outcomes, defined as development of end-stage kidney disease (ESKD) or a 30% decline in estimated glomerular filtration rate (eGFR), was conducted. Baseline and time-updated BPs were modeled using multivariate causal hazards models and marginal structural models (MSMs).

RESULTS

In a median follow-up of 43.5 (interquartile range 27.2, 72.7) months, 367 (24.0%) patients experienced the composite kidney outcomes. No significant associations were found between baseline BP and the composite outcomes. Using MSMs with time-updated SBP for analysis, a U-shaped association was found. In reference to SBP 110-119 mmHg, hazard ratios (95% confidence intervals) for the SBP categories <110, 120-129, 130-139 and ≥140 mmHg were 1.48 (1.02-2.17), 1.13 (0.80-1.60), 2.21 (1.54-3.16) and 2.91 (1.94-4.35), respectively. The trend was more prominent in patients with proteinuria ≥1 g/day and eGFR ≥60 mL/min/1.73 m2. After analyzing time-updated diastolic BP, no similar trend was observed.

CONCLUSIONS

In patients with IgAN, intensive BP control during the treatment period may retard the kidney disease progression, but the potential risk of hypotension still needs to be considered.

Kidney function estimators for drug dose adjustment of direct oral anticoagulants in older adults with atrial fibrillation

Background

The Cockcroft-Gault equation (CrClC-G) is recommended for dose adjustment of direct oral anticoagulant drugs (DOACs) to kidney function. We aimed to assess whether defining DOAC dose appropriateness according to various kidney function estimators changed the associations between dose appropriateness and adverse events in older adults with atrial fibrillation (AF).

Methods

Participants of the Berlin Initiative Study with AF and treated with DOACs were included. We investigated CrClC-G and estimated glomerular filtration rate (eGFR) using the Chronic Kidney Disease Epidemiology Collaboration and European Kidney Function Consortium equations based on creatinine and/or cystatin C. Marginal structural Cox models yielded confounder-adjusted hazard ratios for the risk of mortality, thromboembolism and bleeding associated with dose status.

Results

A total of 224 patients were included in the analysis (median age 87 years). Using CrClC-G, 154 (69%) had an appropriate dose of DOACs, 52 (23%) were underdosed and 18 (8%) were overdosed. During a 39-month median follow-up period, 109 (14.9/100 person-years) participants died, 25 (3.6/100 person-years) experienced thromboembolism and 60 (9.8/100 person-years) experienced bleeding. Dose status was not associated with mortality and thromboembolism, independent of the equation. Underdose status was associated with a lower risk of bleeding with all the equations compared with the appropriate dose group. In participants with discrepancies in dose status using CrClC-G and eGFR equations, the occurrence of endpoints did not differ between participants having an appropriate dose using CrClC-G or eGFR.

Conclusion

In older adults with AF, the association of DOAC dose status with adverse events did not differ when using CrClC-G or eGFR. Our results suggest that eGFR equations are not inferior to CrClC-G within this context.

Association between kidney retransplantation and survival according to age in the French national cohort of dialysis patients

The mean age of patients returning to dialysis after a first kidney transplantation (KT) has increased in the past decades. We aimed to assess the association between second KT (2KT) and survival according to age at the time of return to dialysis. Data of 5334 patients registered in the French Renal Epidemiology and Information Network (REIN) (mean age 56.6 ± 13.6 years) who returned to dialysis after a first KT were collected. The association of 2KT with death was assessed using a propensity score-based analysis taking into account baseline and follow-up variables. In relisted patients (3272 patients, 61.3%), retransplantation was associated with better overall survival in comparison with patients who remained in dialysis (adjusted HR 0.75 [0.63-0.89], p = .0009). The survival advantage conferred by retransplantation gradually declined with increasing age (adjusted HR 0.41 [0.24-0.70] in patients <50, HR 0.94 (0.69-1.27) in patients aged 70 or older, p for interaction 0.034 for age considered as a continuous variable). 2KT is associated with better survival as opposed to remaining on dialysis after a first kidney graft failure. Nevertheless, this survival benefit is age dependent and diminishes with increasing age. The risk/benefit ratio should be comprehensively assessed in the oldest patients when relisting is considered.

Primary prophylaxis for Pneumocystis jirovecii pneumonia in patients receiving rituximab

BACKGROUND

Although previous studies suggested that rituximab increases the risk of Pneumocystis jirovecii pneumonia (PJP), it is uncertain whether its primary prophylaxis for PJP is justified.

RESEARCH QUESTION

Does the benefit of primary prophylaxis for PJP in patients receiving rituximab treatment outweigh the potential risk of the prophylaxis?

STUDY DESIGN AND METHODS

This retrospective study included 3524 patients (hematologic diseases=2500; rheumatic diseases=559; pre/post-solid organ transplantation=465) first exposed to rituximab between 2002 and 2018 in a tertiary referral center in South Korea. Patients were classified into a control group (n=2523) and a prophylaxis group (n=1001) according to the administration of prophylactic TMP-SMX during the first 28 days after the start of rituximab (intention-to-treat analysis). In addition, exposure to TMP-SMX was examined as a time-varying variable (time-varying analysis). Primary outcome was the prophylactic effect of TMP-SMX on the 1-year incidence of PJP. Inverse probability of treatment weights was applied to minimize the baseline imbalance. Secondary outcome included the incidence of adverse drug reactions (ADRs) related to TMP-SMX.

RESULTS

Over 2759.9 person-years, 92 PJP infections occurred, with a mortality rate of 27.2%. The prophylaxis group showed a significantly lower incidence of PJP (adjusted sub-distribution hazard ratio (aSHR), 0.20 [95% CI, 0.10-0.42]) than the control group. This result was consistent with the results of time-varying analysis, in which only one PJP infection occurred during TMP-SMX administration (aSHR, 0.01 [0.003-0.16]). The incidence of adverse drug reactions (ADRs) related to TMP-SMX was 18.1 (14.6-22.2)/100 person-years, and most were of mild-to-moderate severity. Based on ten severe ADRs, the number needed to harm was 101 (61.9-261.1), whereas the number needed to prevent one PJP infection was 32 (24.8-39.4).

INTERPRETATION

TMP-SMX prophylaxis significantly reduces PJP incidence with a tolerable safety profile in patients receiving rituximab treatment.

Medication in adults after atrial switch for transposition of the great arteries: clinical practice and recommendations

Aims

Heart failure is the main threat to long-term health in adults with transposition of the great arteries (TGA) corrected by an atrial switch operation (AtrSO). Current guidelines refrain from recommending heart failure medication in TGA-AtrSO, as there is insufficient data to support the hypothesis that it is beneficial. Medication is therefore prescribed based on personal judgements. We aimed to evaluate medication use in TGA-AtrSO patients and examine the association of use of renin–angiotensin–aldosterone system (RAAS) inhibitors and β-blockers with long-term survival.

Methods and results

We identified 150 TGA-AtrSO patients [median age 30 years (interquartile range 25–35), 63% male] included in the CONCOR registry from five tertiary medical centres with subsequent linkage to the Dutch Dispensed Drug Register for the years 2006–2014. Use of RAAS inhibitors, β-blockers, and diuretics increased with age, from, respectively, 21% [95% confidence interval (CI) 14–40], 12% (95% CI 7–21), and 3% (95% CI 2–7) at age 25, to 49% (95% CI 38–60), 51% (95% CI 38–63), and 41% (95% CI 29–54) at age 45. Time-varying Cox marginal structural models that adjusted for confounding medication showed a lower mortality risk with use of RAAS inhibitors and β-blockers in symptomatic patients [hazard ratio (HR) = 0.13 (95% CI 0.03–0.73); P = 0.020 and HR = 0.12 (95% CI 0.02–0.17); P = 0.019, respectively]. However, in the overall cohort, no benefit of RAAS inhibitors and β-blockers was seen [HR = 0.93 (95% CI 0.24–3.63); P = 0.92 and HR = 0.98 (0.23–4.17); P = 0.98, respectively].

Conclusion

The use of heart failure medication is high in TGA-AtrSO patients, although evidence of its benefit is limited. This study showed lower risk of mortality with use of RAAS inhibitors and β-blockers in symptomatic patients only. These findings can direct future guidelines, supporting use of RAAS inhibitors and β-blockers in symptomatic, but not asymptomatic patients.

Family-based treatment program contributors to child weight loss

BACKGROUND

Multicomponent family-based behavioral treatment (FBT) program for pediatric obesity includes nutrition and physical activity education, as well as behavior therapy techniques. Studies suggest that parent weight loss is the best predictor of child weight loss in FBT. However, given the important role that parents play in the implementation of FBT for their child, isolating the effects of specific FBT treatment component requires consideration of parent influences over time.

METHODS

The following treatment components were assessed: stimulus control (high/low-fat food items in home), nutrition knowledge, energy intake, physical activity, and parental monitoring, as well as weekly anthropometric measures. Adjusted models of interest using inverse probability weights were used to evaluate the effect of specific FBT components on time-varying child weight loss rate, adjusting for time-varying influence of parent weight loss.

RESULTS

One hundred thirty-seven parent-child dyads (CHILD: mean BMI = 26.4 (3.7) and BMIz = 2.0 (0.3); mean age = 10.4 (1.3); 64.1% female; ADULT: mean BMI = 31.9 (6.3); mean age = 42.9 (6.5); 30.1% Hispanic parents; 87.1% female) participated in an FBT program. In traditional model, adult BMI change (b = 0.08; p < 0.01) was the most significant predictor of child weight loss rates and no other treatment components were significant (p's > 0.1). In models that accounted for potential influences from parental weight loss and differential attendance during treatment period, lower availability of high-fat items (b = 1.10, p < 0.02), higher availability of low-fat items (b = 3.73; p < 0.01), and higher scores on parental monitoring practices (b = 1.10, p < 0.01) were associated with greater rates of weight loss, respectively.

CONCLUSION

Results suggest that outside of parent weight change, changes in stimulus control strategies at home and improved parental-monitoring practices are important FBT components for child weight loss.

Evaluation of dyadic changes of parent-child weight loss patterns during a family-based behavioral treatment for obesity

BACKGROUND

Family-based treatment (FBT) for children with overweight and obesity is a package that includes nutrition and physical activity education, as well as parenting and behavior therapy skills. To date, the majority of research suggests that one of the best predictors of child weight loss is parent weight loss. However, the bidirectional processes facilitating parent-child weight loss are not well understood.

OBJECTIVE

To evaluate the strength and direction of parent-child weight-change patterns during a 6-month intervention with FBT for childhood obesity.

METHODS

Parent-child weight change dynamics were evaluated using a bivariate multilevel approach.

RESULTS

Significant positive weight reductions throughout treatment were observed among both parents and children (P's < .01 for both parent and child). In the model adjusting for the conditional influence of attendance over time, parents' initial weight loss was associated with subsequent weight loss by their child (B = 0.102, P < .05; d = 0.352) across the first 10 sessions. Child's weight loss also was associated with subsequent weight loss by their parent (B = 0.105, P < .01; d = 0.412) across the first 10 sessions. A small and negative effects of parents' weight loss on children and children's weight loss on parents from sessions 10 to 20 may have been reflective of slowed rates of weight loss as treatment progressed.

CONCLUSIONS

Together these data suggest that parent-child dyads mutually influence weight loss in FBT. Future studies should leverage how to make best clinical use of these dynamic effects in the context of family-based interventions.