Randomised-controlled trials are particularly scarce and underpowered in the setting of rare diseases: Further acquisition of knowledge is needed

Article type
Authors
El Dib R1, Gomaa H2, Ortiz A3, Politei J4, Kapoor A5, Barreto F6
1Institute of Science and Technology, Unesp—Univ Estadual Paulista, São José dos Campos, Brazil
2Department of Pharmacy, Tanta Chest Hospital, Tanta
3IIS-Fundacion Jimenez Diaz, Universidad Autonoma Madrid
4Neurology Service, Laboratorio Neuroquímica Dr Nestor Chamoles, Buenos Aires
5McMaster Institute of Urology, McMaster University, Hamilton, Ontario
6Department of Internal Medicine, Nephrology Service, Universidade Federal do Paraná
Abstract
Background: Randomised-controlled trials (RCTs) are particularly scarce and underpowered in the setting of rare diseases. The population available to study on Anderson-Fabry disease (AFD) is limited and in some studies long-term follow-up is not available.

Objectives: We present the results of a linear regression and a pooled analysis of proportions from cohort studies to evaluate the efficacy and safety of enzyme replacement therapy (ERT) for AFD in order to complement available information from meta-analysis of RCTs.

Methods: A literature search was performed, from inception to March 2016, using Medline, EMBASE and LILACS. Inclusion criteria were cohort studies, patients with AFD on ERT or natural history, and at least one patient-important outcome reported. The pooled proportion and the confidence interval (CI) are shown for each outcome. Simple linear regressions for composite endpoints were performed.

Results: 77 cohort studies involving 15 305 participants proved eligible. The pooled proportions were as follows: for renal complications, agalsidase alfa 15.3% [95% CI 0.048, 0.303; I2=77.2%, p=0.0005]; agalsidase beta 6% [95% CI 0.04, 0.07; I2 = not applicable]; and untreated patients 21.4% [95% CI 0.1522, 0.2835; I2=89.6%, p