Individual Patient Data Meta-Analysis and Network Meta-Analysis

Pulmonary arterial hypertension treatment: an individual participant data network meta-analysis

BACKGROUND AND AIMS

Effective therapies that target three main signalling pathways are approved to treat pulmonary arterial hypertension (PAH). However, there are few large patient-level studies that compare the effectiveness of these pathways. The aim of this analysis was to compare the effectiveness of the treatment pathways in PAH and to assess treatment heterogeneity.

METHODS

A network meta-analysis was performed using individual participant data of 6811 PAH patients from 20 Phase III randomized clinical trials of therapy for PAH that were submitted to the US Food and Drug Administration. Individual drugs were grouped by the following treatment pathways: endothelin, nitric oxide, and prostacyclin pathways.

RESULTS

The mean (±standard deviation) age of the sample was 49.2 (±15.4) years; 78.4% were female, 59.7% had idiopathic PAH, and 36.5% were on background PAH therapy. After covariate adjustment, targeting the endothelin + nitric oxide pathway {β: 43.7 m [95% confidence interval (CI): 32.9, 54.4]}, nitric oxide pathway [β: 29.4 m (95% CI: 22.6, 36.3)], endothelin pathway [β: 25.3 m (95% CI: 19.8, 30.8)], and prostacyclin pathway [oral/inhaled β: 19.1 m (95% CI: 14.2, 24.0), intravenous/subcutaneous β: 24.4 m (95% CI: 15.1, 33.7)] significantly increased 6 min walk distance at 12 or 16 weeks compared with placebo. Treatments also significantly reduced the likelihood of having clinical worsening events. There was significant heterogeneity of treatment effects by age, body mass index, hypertension, diabetes, and coronary artery disease.

CONCLUSIONS

Drugs targeting the three traditional treatment pathways significantly improve outcomes in PAH, with significant treatment heterogeneity in patients with some comorbidities. Randomized clinical trials are warranted to identify the most effective treatment strategies in a personalized approach.

Comparative efficacy and complications of long-acting and intermediate-acting insulin regimens for adults with type 1 diabetes: an individual patient data network meta-analysis

OBJECTIVE

To examine the comparative efficacy and complications of long-acting and intermediate-acting insulin for different patient characteristics for type 1 diabetes mellitus (T1DM).

DESIGN

Systematic review and individual patient data (IPD) network meta-analysis (NMA).

DATA SOURCES

MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials were searched through June 2015.

ELIGIBILITY CRITERIA

Randomised controlled trials (RCTs) on adults with T1DM assessing glycosylated haemoglobin (A1c) and severe hypoglycaemia in long-acting and intermediate-acting insulin regimens.

DATA EXTRACTION AND SYNTHESIS

We requested IPD from authors and funders. When IPD were not available, we used aggregate data. We conducted a random-effects model, and specifically a one-stage IPD-NMA for those studies providing IPD and a two-stage IPD-NMA to incorporate those studies not providing IPD.

RESULTS

We included 28 RCTs plus one companion report, after screening 6680 titles/abstracts and 205 full-text articles. Of the 28 RCTs, 27 studies provided data for the NMA with 7394 participants, of which 12 RCTs had IPD on 4943 participants. The IPD-NMA for A1c suggested that glargine once daily (mean difference [MD]=-0.31, 95% confidence interval [CI]: -0.48 to -0.14) and detemir once daily (MD=-0.25, 95% CI: -0.41 to -0.09) were superior to neutral protamine Hagedorn (NPH) once daily. NPH once/two times per day improved A1c compared with NPH once daily (MD=-0.30, 95% CI: -0.50 to -0.11). Results regarding complications in severe hypoglycaemia should be considered with great caution due to inconsistency in the evidence network. Accounting for missing data, there was no evidence of inconsistency and long-acting insulin regimens ranked higher regarding reducing severe hypoglycaemia compared with intermediate-acting insulin regimens (two-stage NMA: glargine two times per day SUCRA (Surface Under the Cumulative Ranking curve)=89%, detemir once daily SUCRA=77%; one-stage NMA: detemir once daily/two times per day SUCRA=85%). Using multiple imputations and IPD only, complications in severe hypoglycaemia increased with diabetes-related comorbidities (regression coefficient: 1.03, 95% CI: 1.02 to 1.03).

CONCLUSIONS

Long-acting insulin regimens reduced A1c compared with intermediate-acting insulin regimens and were associated with lower severe hypoglycaemia. Of the observed differences, only glargine once daily achieved a clinically significant reduction of 0.30%. Results should be interpreted with caution due to very low quality of evidence.

PROSPERO REGISTRATION NUMBER

CRD42015023511.