The Value of Case Reports in Systematic Reviews from Rare Diseases. The Example of Enzyme Replacement Therapy (ERT) in Patients with Mucopolysaccharidosis Type II (MPS-II).

Miguel Sampayo-Cordero,Andrea Malfettone,José Manuel Pérez-García,Antonio Llombart-Cussac,Almudena Pardo,Bernat Miguel-Huguet,Javier Cortés,Jordi Pérez-López

doi:10.3390/ijerph17186590

Abstract

Background: Case reports are usually excluded from systematic reviews. Patients with rare diseases are more dependent on novel individualized strategies than patients with common diseases. We reviewed and summarized the novelties reported by case reports in mucopolysaccharidosis type II (MPS-II) patients treated with enzyme replacement therapy (ERT). Methods: We selected the case reports included in a previous meta-analysis of patients with MPS-II treated with ERT. Later clinical studies evaluating the same topic of those case reports were reported. Our primary aim was to summarize novelties reported in previous case reports. Secondary objectives analyzed the number of novelties evaluated in subsequent clinical studies and the time elapsed between the publication of the case report to the publication of the clinical study. Results: We identified 11 innovative proposals in case reports that had not been previously considered in clinical studies. Only two (18.2%) were analyzed in subsequent nonrandomized cohort studies. The other nine novelties (81.8%) were analyzed in later case reports (five) or were not included in ulterior studies (four) after more than five years from their first publication. Conclusions: Case reports should be included in systematic reviews of rare disease to obtain a comprehensive summary of the state of research and offer valuable information for healthcare practitioners.

Highlights

Rare diseases and ultra-rare diseases are defined by a prevalence of ≤50 patients and ≤1 patient per100,000 people, respectively
The systematic review included case reports of mucopolysaccharidosis type II (MPS-II) patients who were treated with enzyme replacement therapy (ERT), and the search was carried out in Excerpta Medica Database (EMBASE), Medical Literature Analysis and Retrieval System Online (MEDLINE), The Cochrane Library
The time elapsed between the publication of a case report including a specific novelty and the follow-up clinical study or studies was calculated subtracting the date of the first clinical study to the date of the first case report analyzing such novelty

Summary

Introduction

Rare diseases and ultra-rare diseases are defined by a prevalence of ≤50 patients and ≤1 patient per. This low prevalence of such diseases makes the conduction of randomized. We reviewed and summarized the novelties reported by case reports in mucopolysaccharidosis type. Methods: We selected the case reports included in a previous meta-analysis of patients with MPS-II treated with ERT. Later clinical studies evaluating the same topic of those case reports were reported. Our primary aim was to summarize novelties reported in previous case reports. Secondary objectives analyzed the number of novelties evaluated in subsequent clinical studies and the time elapsed between the publication of the case report to the publication of the clinical study. Results: We identified 11 innovative proposals in case reports that had not been previously considered in clinical studies.

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Discussion

Conclusion