Non-English reports of medical research

Understanding and Evaluating Systematic Reviews and Meta-analyses

A systematic review is a summary of existing evidence that answers a specific clinical question, contains a thorough, unbiased search of the relevant literature, explicit criteria for assessing studies and structured presentation of the results. A systematic review that incorporates quantitative pooling of similar studies to produce an overall summary of treatment effects is a meta-analysis. A systematic review should have clear, focused clinical objectives containing four elements expressed through the acronym PICO (Patient, group of patients, or problem, an Intervention, a Comparison intervention and specific Outcomes). Explicit and thorough search of the literature is a pre-requisite of any good systematic review. Reviews should have pre-defined explicit criteria for what studies would be included and the analysis should include only those studies that fit the inclusion criteria. The quality (risk of bias) of the primary studies should be critically appraised. Particularly the role of publication and language bias should be acknowledged and addressed by the review, whenever possible. Structured reporting of the results with quantitative pooling of the data must be attempted, whenever appropriate. The review should include interpretation of the data, including implications for clinical practice and further research. Overall, the current quality of reporting of systematic reviews remains highly variable.

[Hand searching for controlled clinical trials in German surgical journals. A contribution to evidence-based surgery]

BACKGROUND

The identification of all available and relevant study reports is mandatory for a comprehensive assessment of randomised (RCTs) and controlled clinical trials (CCTs) in systematic reviews. Incomplete compilation of health care journals in electronic databases and incorrect indexing of the studies impair the result of a systematic literature search. An additional search in medical journals that are not listed in electronic databases can obtain higher search precision.

METHODS

In the hand searching project of the Cochrane Collaboration, in Germany 14 surgical journals were searched manually for RCTs and CCTs. The identified study reports were compared with Medline records, and the publication frequency was analysed. The study reports were published in the Cochrane Library and are henceforth available for inclusion in systematic reviews.

RESULTS

Four hundred (77%) of the 519 published volumes in the 14 surgical journals were searched for RCTs and CCTs. Of the 1152 controlled trials (670 RCTs and 482 CCTs) identified, 674 (58%) were not included in Medline.

CONCLUSIONS

The gap between the number of hand search results and the number of Medline indexed RCTs and CCTs is also reflected in other special medical fields. To ensure completeness of the literature compilation, the hand searching project should be continued.

[Randomized controlled and controlled clinical trials in German-language ophthalmological journals]

BACKGROUND

The medical database MEDLINE contains only a part of all published randomized controlled (RCTs) and controlled clinical (CCTs) trials. The validity of a systematic review depends on the complete consideration of all studies pertaining to a clinical question. Therefore, a manual systematic search in medical journals is mandatory.

METHODS

The last 30 years of the three peer-reviewed German-language ophthalmological journals Der Ophthalmologe, Klinische Monatsblätter für Augenheilkunde, and Spektrum der Augenheilkunde were retrospectively searched for controlled trials. All identified RCTs and CCTs were classified according to their ophthalmological subspecialty. The quality of the studies was evaluated using the CONSORT Statement. Moreover, a comparison was made of how many of the studies identified by hand searching are registered in MEDLINE and correctly classified as RCTs/CCTs.

RESULTS

In total 984 RCTs and CCTs were identified; 62% of the trials were from the subspecialty anterior eye segment, 14% belonged to the subspecialty posterior eye segment, and 18% belonged to glaucoma. A sample size calculation was reported in less than 2% of the full-text publications and 34% reported a blinded study design. A randomization process was described in 23% of the RCTs. Most controlled trials were published in the 1990s in all three journals. From 1998 onward, there was a decrease in the number of published controlled trials in the reviewed German literature. About 63% of the studies registered in MEDLINE are correctly classified.

CONCLUSION

In the specialty of ophthalmology there are many important studies which provide basic information for compilation of systematic reviews and clinical guidelines. However, many of the identified clinical trials in German-language journals show deficiencies in the study quality. Only a part of the identified controlled trials are correctly classified in MEDLINE. Therefore, a retrospective registration is essential to complete the electronic database in ophthalmology.

[Randomized and nonrandomized controlled clinical trials in a German surgical journal]

BACKGROUND

Comprehensive identification of relevant literature is mandatory for valid assessment of the effectiveness of surgical interventions. Thus, electronic database searches are often complemented by handsearching of relevant surgical journals. The aim of this study was to assess the quantity and quality of randomized controlled (RCTs) and controlled clinical trials (CCTs) in the German surgical journal Der Chirurg.

METHODS

Quantitative and qualitative assessment was made after handsearching of studies published from 1948 to 2005 in Der Chirurg. Systematic database search (MEDLINE) was used for comparison of RCTs published in Der Chirurg and international surgical journals.

RESULTS

Overall, 112 controlled clinical trials (90 RCTs, 22 CCTs) were identified by handsearching. The implementation of sample size calculation was reported in 12 of 90 (13%) RCTs. Forty-six (51%) did not specify the randomization process, and five (6%) incorporated the "intention to treat" principle in their analyses. After 2000, RCTs were published in declining frequency in Der Chirurg, whereas international surgical journals printed stable quantities of these studies.

CONCLUSION

Improving the prerequisites of patient-centered clinical research in surgery, rigorous implementation of principles of the CONSORT statement, and modified publication strategies may improve the quality and quantity of reports on clinical studies in Germany.

Effect of technique on intraocular pressure after combined cataract and glaucoma surgery: An evidence-based review

TOPIC

To analyze the literature pertaining to the techniques used in combined cataract and glaucoma surgery, including the technique of cataract extraction, the timing of the surgery (staged procedure versus combined procedure), the anatomic location of the operation, and the use of antifibrosis agents.

CLINICAL RELEVANCE

Cataract and glaucoma are both common conditions and are often present in the same patient. There is no agreement concerning the optimal surgical management of these disorders when they coexist.

METHODS/LITERATURE REVIEWED

Electronic searches of English language articles published since 1964 were conducted in Pub MED and CENTRAL, the Cochrane Collaboration's database. These were augmented by a hand search of six ophthalmology journals and the reference lists of a sample of studies included in the literature review. Evidence grades (A, strong; B, moderate; C, weak; I, insufficient) were assigned to the evidence that involved a direct comparison of alternative techniques.

RESULTS

The preponderance of evidence from the literature suggests a small (2-4 mmHg) benefit from the use of mitomycin-C (MMC), but not 5-fluorouracil (5-FU), in combined cataract and glaucoma surgery (evidence grade B). Two-site surgery provides slightly lower (1-3 mmHg) intraocular pressure (IOP) than one-site surgery (evidence grade C), and IOP is lowered more (1-3 mmHg) by phacoemulsification than by nuclear expression in combined procedures (evidence grade C). There is insufficient evidence to conclude either that staged or combined procedures give better results or that alternative glaucoma procedures are superior to trabeculectomy in combined procedures.

CONCLUSIONS

In the literature on surgical techniques and adjuvants used in the management of coexisting cataract and glaucoma, the strongest evidence of efficacy exists for using MMC, separating the incisions for cataract and glaucoma surgery, and removing the nucleus by phacoemulsification.