Evaluation of existing systematic reviews

Author Year

Journal/Source
Intervention or exposureOutcomeStudy design includedHealthy population at baseline?*Only included Ca +− Vit D interventions? **
Reported baseline dietary Ca intake with dietary assessment methods?***
Clear reporting of comparison and control group?Clear reporting of outcome definitions?Clear reporting of study designs (need separate reporting if two or more different designs are included)?Comments****
Autier 2007
Arch Intern Med
[17846391]1
Vitamin D [+/− Calcium]All cause mortalityRCTsYes1YesYesYesYesOne additional study found
Avenell 2008
Cochrane Database of Systematic Reviews
[16034849]2
Vitamin D [+/− Calcium]All cause mortalityRCTsYesYesYesYesYesAll relevant studies included in Autier 2007 – Conclusions are same as Autier 2007.
Allender 1996
Ann Intern Med
Ca supplementBlood pressureRCTYes (subgroup analysis)YesYesYesYes26 of 64 potential RCTs
Cappuccio 1995
AJE
Ca intakeBlood pressureObservational, including cross- sectionalUnclearNoNA (regressions)YesNoREJECT Includes XS
Dickinson 2008
Cochrane
Ca supplementBlood pressureRCTNo
All with HTN
YesYesYesYesRevision of 2006 SR 15/64 potential RCTs
Griffith 1999
AJH
Ca supplementBlood pressureRCTYes & No HTN & NTN combined See commentYesYesYesYesUpdate of Bucher 1996 [2263] Subgp analysis HTN vs NTN in Bucher only 42/64 potential RCTs
van Mierlo 2006
J Hum Hypert
Ca supplementBlood pressureRCTYes
Subgroup of HTN & NTN
YesYesYesYes40/64 potential RCTs
Trumbo 2007
Nutr Rev
Ca supplementBlood pressure, HTN, Pregnancy-induced HTNAllYes
Subgroup of HTN & NTN
Yes (interv)
No (observ)
NoNoNoREJECT Qualitative only Count of sig studies only Unclear if SR.
Bergsma-Kadijk1996

Epidemiology
Ca intakecancer and polypCohort and Case-controlnd (probably healthy population)nd on dietary assessment methodnd on Ca intake (only RR/OR between lowest and highest categories reported)ndnd on the definition of case-control studyReject
Weigarten 2008
Cochrane Database of Systematic Reviews
Ca supplement (>1200 mg/d)cancer and polypRCTyes (pts with prior adenoma)yesyesyesyesAccept
Davies 2006

J Natl Cancer Inst
Nutritional RCTs, including Ca supplementCancer, recurrence of preinvasive lesionsRCTNo (both pts with cancer and preinvasive lesions)ndnonoyesPart of a larger SR of both diet and physical activity on outcome among patients with cancer or preinvasive lesions
Bergel 2007

BMC Pediatrics
maternal calcium intakeoffspring BPRCTs & cohorty (RCT)no
yes
yesyesnoData from 2 RCTs may be useful. Reject
Carroli 1994
Brit J Obstet Gynecol
Ca supplementPreeclampsiaRCTYesYesYesYesYesCovered by latest Cochrane SR
Hofmeyer 2003
S African J
Ca SupplementPreeclampsiaRCTYesYesYesYesYesCovered by latest Cochrane SR
Hofmeyer 2007
S African J
Ca SupplementPreeclampsia(and summary of the outcomes mentioned above)RCTYesYesYesYesYesCovered by latest Cochrane SR
Hoffmeyr 2006
Cochrane Database of Systematic Reviews
Ca supplementPreeclampsia, pregnancy induced hypertension with and without proteinuria, maternal death or serious morbidity, other maternal outcomes, stillbirth, neonatal mortality or morbidity, preterm birth, small gestational age, and other outcomes for the childRCTYesYesYesYesYesEligible review
Bucher 1996
JAMA
Ca supplementPreeclampsia, pregnancy-induced hypertensionRCTYesYesYesYesYesCovered by latest Cochrane SR
Gao 2005

NCI
calcium intake or dairy productprostate cancerprospective cohortyes (assumed from study design)yesyesyesyes
Shaukat 2005

Am J Gastroenterol
Ca supplementrecurrent polypRCTyes (pts with prior adenoma)no (1/3 included Ca+Vit A/C/E+selenium)yesyes? “recurrence of adenoma”yes? “RCTReject
Barr 2003
J Nutr
Increased dairy product or calcium intake (from supplements)WeightRCTsYes “healthy”Yes (separate studies of increased dairy product and those of calcium supplements)yesyesyesNo meta-analysis. Included children and adults
Trowman 2006
Br J Nutr
Calcium supplements or increased provision of dairy productsWeightRCTsYes (excluded populations with severe co-morbidities, such as renal problems or cancer)Yes (Separate meta-analyses for calcium supplement and increased provision of dairy products)yesyesyesMay need to redo the meta-analyses to separate out energy restriction diet studies. This SR included adults only.
Winzenberg 2007

Obesity
calcium supplementation food or chemicalweightRCTsyesyesyesyesyes2° analysis of RCT of calcium on bone density outcome
Lanou 2008
Nutr Rev
Calcium or dairy supplementation with or without energy restrictionWeight, body fatRCTsndyesnoyesyesIncluded both dairy and calcium supplementation RCTs. No individual study characteristics reported
*

Either included only healthy population at baseline or SR had separate analyses for population with diseases and without diseases

**

For SR of interventional studies

***

For SR of observational studies

****

Please comment on issues such as update of previous SRs or specific reasons for using or not using the SR, other than not fulfilling the screening criteria.

From: Appendix D, Evaluation of existing systematic reviews and evidence tables of the qualified systematic reviews

Cover of Vitamin D and Calcium
Vitamin D and Calcium: A Systematic Review of Health Outcomes.
Evidence Reports/Technology Assessments, No. 183.
Chung M, Balk EM, Brendel M, et al.

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