Should systematic reviews include non-randomized and uncontrolled studies? The case of acupuncture for chronic headache
Language: 
English
Short Title: 
Should systematic reviews include non-randomized and uncontrolled studies?
Abstract: 

We aimed to investigate: (1) whether patient and intervention characteristics, design-independent quality aspects, and response rates differ between randomized and non-randomized trials of acupuncture for chronic headache; (2) whether non-randomized studies provide useful additional information (regarding long-term effects, prognostic factors, adverse effects, and generalizability); (3) reasons for potential differences in response rates. Studies including at least five patients and reporting clinical outcome data were identified through searches in Medline, Embase, the Cochrane Controlled Trials Register, other databases and checking of bibliographies. Twenty-four randomized trials and 35 non-randomized studies (five non-randomized controlled cohort studies, 10 prospective uncontrolled studies, 10 case series, and 10 cross-sectional surveys) met the inclusion criteria. Studies were heterogeneous regarding patients, interventions, outcome measurements and results. On average, randomized trials had smaller sample sizes, met more quality criteria, and had lower response rates (0.59 [95% confidence interval 0.48-0.69] vs. 0.78 [0.72-0.83]). Whether randomized or not, studies meeting more quality criteria had lower response rates. Non-randomized studies did not have significantly longer follow-up periods, three included an analysis of prognostic variables, only one reported on adverse effects, and the degree of generalizability was unclear. In the case of acupuncture for chronic headache, non-randomized studies confirmed the finding of a systematic review of randomized trials that the treatment is likely to be effective but provided little relevant additional information on long-term effects, prognostic factors, and adverse effects.

Author(s): 
Linde, Klaus
Scholz, Michael
Melchart, Dieter
Willich, Stefan N.
Item Type: 
Journal Article
Publication Title: 
Journal of Clinical Epidemiology
Journal Abbreviation: 
J Clin Epidemiol
Publication Date: 
2002-01
Publication Year: 
2002
Pages: 
77-85
Volume: 
55
Issue: 
1
ISSN: 
0895-4356
Library Catalog: 
PubMed
Extra: 
PMID: 11781125

Turabian/Chicago Citation

Klaus Linde, Michael Scholz, Dieter Melchart and Stefan N. Willich. 2002-01. "Should systematic reviews include non-randomized and uncontrolled studies? The case of acupuncture for chronic headache." Journal of Clinical Epidemiology 55: 1: 77-85.

Wikipedia Citation

<ref> {{Cite journal | doi = | issn = 0895-4356 | volume = 55 | pages = 77-85 | last = Linde | first = Klaus | coauthors = Scholz, Michael, Melchart, Dieter, Willich, Stefan N. | title = Should systematic reviews include non-randomized and uncontrolled studies? The case of acupuncture for chronic headache | journal = Journal of Clinical Epidemiology | date = 2002-01 | pmid = | pmc = }} </ref>