Advertisement
Table 1 Descriptive characteristics of included studies (n = 60)
| Study characteristic | Number of studies (%) |
|---|---|
| Year of publication | |
| 1990–1994 | 1 (2) |
| 1995–1999 | 2 (3) |
| 2000–2004 | 3 (5) |
| 2005–2009 | 7 (12) |
| 2010–2014 | 39 (65) |
| 2015-present (June 21, 2017) | 8 (13) |
| Country (corresponding author address) | |
| United States | 27 (45) |
| United Kingdom | 5 (8) |
| Canada | 8 (13) |
| France | 4 (7) |
| The Netherlands | 6 (10) |
| Germany | 3 (5) |
| Italy | 4 (7) |
| Belgium | 1 (2) |
| Ireland | 1 (2) |
| Australia | 1 (2) |
| Sponsorship | |
| Industry affiliations | 16 (27) |
| None (no conflicts of interest declared) | 24 (40) |
| Other (e.g., government funding) | 6 (10) |
| Not explicitly reported | 14 (23) |
| Disease/disease group of focus | |
| Rare diseases in general | 33 (55) |
| Disease groups: | |
| Inherited metabolic diseasesa | 2 (3) |
| Lysosomal storage disorders | 3 (5) |
| Pediatric rheumatic diseases | 1 (2) |
| Rare lung diseases | 2 (3) |
| Rare neonatal diseases | 1 (2) |
| Rare neurodegenerative diseases | 1 (2) |
| Rare renal diseases | 1 (2) |
| Individual disease(s): | |
| Alpha1-antitrypsin deficiency & pulmonary alveolar proteinosis | 1 (2) |
| Batten Disease | 1 (2) |
| Childhood polyarteritis nodosa | 2 (3) |
| Duchenne muscular dystrophy | 1 (2) |
| Familial hypercholesterolemia | 1 (2) |
| Familial Mediterranean fever | 1 (2) |
| Gaucher disease | 1 (2) |
| Hemophilia A | 1 (2) |
| Late-onset Pompe disease | 1 (2) |
| Non-dystrophic mytonia | 1 (2) |
| Pediatric multiple sclerosis & Creutzfeldt-Jakob disease | 1 (2) |
| Primary sclerosing cholangitis | 1 (2) |
| Scleroderma | 2 (3) |
| Vasculitis (rare form) | 1 (2) |
| Types of studies | |
| Review article of multiple research methods | 28 (47) |
| Review article of a single research method | 11 (18) |
| Application/case example of research method | 17 (28) |
| Key article that operationalized steps for the research method | 3 (5) |
| Other | 1 (2) |
| Research paradigm discusseda | |
| Explanatory evidence generation | 35 (58) |
| Comparative effectiveness/pragmatic evidence generation | 30 (50) |
| Patient-oriented evidence generation | 15 (25) |
