Calcium and phosphorus supplementation of human milk for preterm infants

Jane E Harding; Jess Wilson; Julie Brown

doi:10.1002/14651858.CD003310.pub2

Tambahan kalsium dan fosforus kepada susu ibu untuk bayi lahir pramatang

Contraer todo Desplegar todo

Referencias

References to studies included in this review

Ir a:

estudios excluidos
estudios a la espera de valoración
otras referencias
otras versiones publicadas

Torabi Z, Moemeni N, Ahmadiafshar A, Mazloomzadeh S. The effect of calcium and phosphorus supplementation on metabolic bone disorders in premature infants. JPMA. The Journal of the Pakistan Medical Association 2014;64(6):635‐9. [PUBMED: 25252480]

Torabi Z, Moemeni N, Mazloozadeh S. Evaluation and comparison of calcium and phosphorus in the improvement of metabolic bone disorder in premature infants. Archives of Disease in Childhood. 2012; Vol. 97:A386. [DOI: 10.1136/archdischild‐2012‐302724.1354]

Google Scholar

References to studies excluded from this review

Ir a:

estudios incluidos
estudios a la espera de valoración
otras referencias
otras versiones publicadas

Atkinson SA, Whyte RK, Fraser D, Stanhope R. A randomized trial of calcium and phosphorus supplements in low birthweight infants fed mother's milk. Proceedings of the Canadian Federation of Biological Sciences 1989;32:Abstract.

Google Scholar

Carroll WF, Fabres J, Nagy TR, Frazier M, Roane C, Pohlandt F, et al. Results of extremely‐low‐birth‐weight infants randomized to receive extra enteral calcium supply. Journal of Pediatric Gastroenterology and Nutrition 2011;53(3):339‐45.

Faerk J, Petersen S, Petersen B, Michaelsen KF. Diet and bone mineral content at term in premature infants. Pediatric Research 2000;47(1):148‐56.

Greer FR, McCormick A. Improved bone mineralization and growth in premature infants fed fortified own mother's milk. Journal of Pediatrics 1988;112(6):961‐9.

Gross SJ. Bone mineralization in preterm infants fed human milk with and without mineral supplementation. Journal of Pediatrics 1987;111(3):450‐8.

Gupta G. Unpublished data.

Hall RT, Wheeler RE, Rippetoe LE. Calcium and phosphorus supplementation after initial hospital discharge in breast‐fed infants of less than 1800 grams birth weight. Journal of Perinatology 1993;13(4):272‐8.

Lucas A, Fewtrell MS, Morley R, Lucas PJ, Baker BA, Lister G, et al. Randomized outcome trial of human milk fortification and developmental outcome in preterm infants. American Journal of Clinical Nutrition 1996;64(2):142‐51.

Salle B, Senterre J, Putet G, Rigo J. Effects of calcium and phosphorus supplementation on calcium retention and fat absorption in preterm infants fed pooled human milk. Journal of Pediatric Gastroenterology and Nutrition 1986;5(4):638‐42.

Sann L, Loras B, David L, Durr F, Simonnet C, Baltassat P, et al. Effect of phosphorus supplementation to breast fed very low birthweight infants on urinary calcium excretion, serum immunoreactive parathyroid hormone and plasma 1,25‐dihydroxy‐vitamin D concentration. Acta Paediatrica Scandinavica 1985;74(5):664‐8.

Schanler RJ, Garza C. Improved mineral balance in very low birth weight infants fed fortified human milk. Journal of Pediatrics 1988;112(3):452‐6.

Senterre J, Putet G, Salle B, Rigo J. Effects of vitamin D and phosphorus supplementation on calcium retention in preterm infants fed banked human milk. Journal of Pediatrics 1983;103(2):305‐7.

References to studies awaiting assessment

Ir a:

estudios incluidos
estudios excluidos
otras referencias
otras versiones publicadas

Boehm G, Kirchner B. Calcium and phosphorus homeostasis in very‐low‐birth‐weight infants appropriate for gestational age fed human milk. Biomedica Biochimica Acta 1988;47(6):529‐36.

Kamali K, Pishva N, Deireh E. The effects of low and high dose oral calcium and phosphor supplementation on nephrocalcinosis diagnosed by sonography in premature and low birth weight neonates. Iranian Journal of Medical Sciences 2014;39(6):559‐64. [PUBMED: 25429179]

Additional references

Ir a:

estudios incluidos
estudios excluidos
estudios a la espera de valoración
otras versiones publicadas

American Academy of Pediatrics Committee on Nutrition. In: KleinmanRE , Greer FR editor(s). Pediatric Nutrition Handbook. Elk Grove Village, IL: American Academy of Pediatrics, 2014.

Atkinson SA, Radde IC, Anderson GH. Macromineral balances in premature infants fed their own mothers' milk or formula. Journal of Pediatrics 1983;102(1):99‐106.

Bhatia J. Human milk and the premature infant. Journal of Perinatology 2007;27:s71‐4.

Bozzetti V, Tagliabue P. Metabolic bone disease in preterm newborn: an update on nutritional issues. Italian Journal of Pediatrics 2009;35:20.

Brown JVE, Embleton ND, Harding JE, McGuire W. Multi‐nutrient fortification of human milk for preterm infants. Cochrane Database of Systematic Reviews 2016, Issue 5. [DOI: 10.1002/14651858.CD000343.pub3]

GRADEpro Guideline Development Tool [Software] [Computer program]. GRADEpro GDT. GRADEpro.org: McMaster University (developed by Evidence Prime, Inc.), 2015.

Guyatt G, Oxman AD, Akl EA, Kunz R, Vist G, Brozek J, et al. GRADE guidelines: 1. Introduction ‐ GRADE evidence profiles and summary of findings tables. Journal of Clinical Epidemiology 2011;64(4):383‐94. [PUBMED: 21195583]

Guyatt GH, Oxman AD, Vist G, Kunz R, Brozek J, Alonso‐Coello P, et al. GRADE guidelines: 4. Rating the quality of evidence ‐ study limitations (risk of bias). Journal of Clinical Epidemiology 2011;64(4):407‐15. [PUBMED: 21247734]

Guyatt GH, Oxman AD, Kunz R, Brozek J, Alonso‐Coello P, Rind D, et al. GRADE guidelines 6. Rating the quality of evidence ‐ imprecision. Journal of Clinical Epidemiology 2011;64(12):1283‐93. [PUBMED: 21839614]

Guyatt GH, Oxman AD, Kunz R, Woodcock J, Brozek J, Helfand M, et al. GRADE guidelines: 7. Rating the quality of evidence ‐ inconsistency. Journal of Clinical Epidemiology 2011;64(12):1294‐302. [PUBMED: 21803546]

Guyatt GH, Oxman AD, Kunz R, Woodcock J, Brozek J, Helfand M, et al. GRADE guidelines: 8. Rating the quality of evidence ‐ indirectness. Journal of Clinical Epidemiology 2011;64(12):1303‐10. [PUBMED: 21802903]

Higgins JPT, Green S (editors). Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 [updated March 2011]. The Cochrane Collaboration, 2011. www.cochrane‐handbook.org.

Itani O, Tsang RC. Calcium, phosphorus, and magnesium in the newborn: pathophysiology and management. In: Hay WW editor(s). Neonatal Nutrition and Metabolism. St. Louis: Mosby‐Year Book, Inc., 1991:171‐202.

Google Scholar

Kuschel CA, Harding JE. Multicomponent fortified human milk for promoting growth in preterm infants (Cochrane Review). Cochrane Database of Systematic Reviews 1998, Issue Issue 4. [DOI: 10.1002/14651858.CD000343]

Google Scholar

The Nordic Cochrane Centre, The Cochrane Collaboration. Review Manager (RevMan). Version 5.2. Copenhagen: The Nordic Cochrane Centre, The Cochrane Collaboration, 2013.

Rowe JC, Wood DH, Rowe DW, Raisz LG. Nutritional hypophosphatemic rickets in a premature infant fed breast milk. New England Journal of Medicine 1979;300(6):293‐6.

Rowe J, Rowe D, Horak E, et al. Hypophosphatemia and hypercalciuria in small premature infants fed human milk: evidence for inadequate dietary phosphorus. Journal of Pediatrics 1984;104(1):112‐7.

Schell‐Feith EA, Kist‐van Holthe JE, van der Heijden AJ. Nephrocalcinosis in preterm neonates. Pediatric Nephrology 2010;25:221.

Schünemann H, Brożek J, Guyatt G, Oxman A, editors. GRADE Working Group. GRADE Handbook for Grading Quality of Evidence and Strength of Recommendations. www.guidelinedevelopment.org/handbook.Updated October 2013.

Google Scholar

Winsloe C, Earl S, Dennison EM, Cooper C, Harvey NC. Early life factors in the pathogenesis of osteoporosis. Current Osteoporosis Reports 2009;7(4):140‐4.

References to other published versions of this review

Ir a:

estudios incluidos
estudios excluidos
estudios a la espera de valoración
otras referencias

Kuschel CA, Harding JE, Kumaran VS. Calcium and phosphorus supplementation of human milk for preterm infants. Cochrane Database of Systematic Reviews 2001, Issue 4. [DOI: 10.1002/14651858.CD003310]

Characteristics of studies

Characteristics of included studies [ordered by study ID]

Ir a:

estudios excluidos
estudios a la espera de clasificación

Torabi 2014

Methods	Parallel randomised controlled trial
Participants	Number of babies: 40 Gestational age (mean (SD)): intervention: 33.3 (1.7); control: 33.3 (1.8) Inclusion criteria: gestational age < 37 weeks and birth weight < 2500 grams; medically stable and breastfed only Exclusion criteria: "Neonates with TPN and being nil per oral (NPO) for more than one week, receiving medications interfering with vitamin D metabolism (anticonvulsants, diuretics, corticosteroids etc.), those with sepsis syndrome, significant respiratory, neurologic, renal, genetic, cardiovascular, hepatic or gastrointestinal diseases as well as neonates whose mothers had osteomalacia, diabetes, parathyroid gland disease and renal disorders were excluded from the study” (Subjects and Methods, p.636) Setting: Valie‐e‐Asr Hospital of Zanjan City, in Iran Timing: December 2010‐June 2011
Interventions	Intervention: calcium 45 mg/kg/d and phosphorus 24 mg/kg/d supplement (in addition to breast milk and vitamin D) (n = 20) vs Control: breast milk and Vitamin D only (n = 20)
Outcomes	Prespecified outcomes: ‐ Serum calcium, phosphorus and alkaline phosphatase levels ‐ measured every 2 weeks ‐ Growth parameters (weight, height, head circumference) ‐ measured every 2 weeks ‐ Osteopenia ‐ assessed by wrist X‐ray at end of study
Notes	Funding: not stated Intention‐to‐treat analysis: yes
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"Randomly divided into two groups" (p.636)
Allocation concealment (selection bias)	Unclear risk	This was not stated
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Clinician: "All neonates received supplements and/or vitamin D at the ages of 10 days to 6 weeks by mothers under the supervision of a qualified person who did not have any role in data analysis" (p.636) Although they did not have a role in data analysis, this does not mean that they were blinded
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Outcome assessor was not aware of the study "At the 6th week, an x‐ray of left wrist + physical exam was done by an expert and a pediatrician without being informed about the research project" (p.636)
Incomplete outcome data (attrition bias) All outcomes	Low risk	No loss to follow‐up was reported
Selective reporting (reporting bias)	Low risk	All outcomes specified were reported
Other bias	Low risk	Groups were similar at baseline

Characteristics of excluded studies [ordered by study ID]

Ir a:

estudios incluidos
estudios a la espera de clasificación

Study	Reason for exclusion
Atkinson 1989	Published in abstract form only, with no clinical results available (data lost)
Carroll 2011	Both intervention and control groups received supplementation
Faerk 2000	No randomisation to unsupplemented control group
Greer 1988	Supplementation with calcium, phosphate and protein. This study is included in the review on multi‐component fortification (Brown 2016)
Gross 1987	Mineral supplementation was provided in the form of multi‐component fortifier or premature formula. This study is included in the multi‐component fortification review (Brown 2016)
Gupta (unpublished data)	Comparision of unsupplemented human milk vs human milk supplemented with calcium and with calcium and phosphorus. Concerns about the randomisation process and disparity between control and treatment groups
Hall 1993	Intervention performed on preterm infants at discharge from hospital
Lucas 1996	Supplementation of human milk with a multi‐component fortifier vs supplementation with phosphate alone. This study is included in the review on multi‐component fortification (Brown 2016)
Salle 1986	No prespecified clinical outcomes. All outcomes biochemical
Sann 1985	No prespecified clinical outcomes. Outcomes biochemical (urinary calcium and phosphate losses)
Schanler 1988	Not randomised
Senterre 1983	Not randomised

Characteristics of studies awaiting assessment [ordered by study ID]

Ir a:

estudios incluidos
estudios excluidos

Boehm 1988

Methods	Not known
Participants	Not known
Interventions	Not known
Outcomes	Not known
Notes

Kamali 2014

Methods	"Randomized controlled trial"
Participants	37 preterm infants with birth weight < 1500 g or gestational age < 34 weeks
Interventions	Two different doses of calcium (75 vs 230 mg/kg/d) and phosphorus (50 vs 110 mg/kg/d) were prescribed; laboratory and sonographic data were then documented and evaluated
Outcomes	Nephrocalcinosis
Notes	Unclear if this study meets inclusion criteria for this review. Study authors are being contacted

Data and analyses

Open in table viewer

Comparison 1. Calcium supplementation versus no calcium supplementation

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Weight (g) Show forest plot	1		Mean Difference (IV, Fixed, 95% CI)	Subtotals only
Open in figure viewer Analysis 1.1 Comparison 1 Calcium supplementation versus no calcium supplementation, Outcome 1 Weight (g).
1.1 Weight at 2 weeks	1	40	Mean Difference (IV, Fixed, 95% CI)	52.5 [‐155.44, 260.44]
1.2 Weight at 4 weeks	1	40	Mean Difference (IV, Fixed, 95% CI)	60.00 [‐151.39, 271.39]
1.3 Weight at 6 weeks	1	40	Mean Difference (IV, Fixed, 95% CI)	138.5 [‐82.16, 359.16]
2 Length (cm) Show forest plot	1		Mean Difference (IV, Fixed, 95% CI)	Subtotals only
Open in figure viewer Analysis 1.2 Comparison 1 Calcium supplementation versus no calcium supplementation, Outcome 2 Length (cm).
2.1 Length at 2 weeks	1	40	Mean Difference (IV, Fixed, 95% CI)	0.34 [‐1.36, 2.04]
2.2 Length at 4 weeks	1	40	Mean Difference (IV, Fixed, 95% CI)	0.47 [‐1.20, 2.14]
2.3 Length at 6 weeks	1	40	Mean Difference (IV, Fixed, 95% CI)	0.77 [‐0.93, 2.47]
3 Head circumference (cm) Show forest plot	1		Mean Difference (IV, Fixed, 95% CI)	Subtotals only
Open in figure viewer Analysis 1.3 Comparison 1 Calcium supplementation versus no calcium supplementation, Outcome 3 Head circumference (cm).
3.1 Head circumference at 2 weeks	1	40	Mean Difference (IV, Fixed, 95% CI)	0.19 [‐0.42, 0.80]
3.2 Head circumference at 4 weeks	1	40	Mean Difference (IV, Fixed, 95% CI)	0.22 [‐0.39, 0.83]
3.3 Head circumference at 6 weeks	1	40	Mean Difference (IV, Fixed, 95% CI)	0.33 [‐0.30, 0.96]
4 Serum alkaline phosphatase Show forest plot	1		Mean Difference (IV, Fixed, 95% CI)	Subtotals only
Open in figure viewer Analysis 1.4 Comparison 1 Calcium supplementation versus no calcium supplementation, Outcome 4 Serum alkaline phosphatase.
4.1 Serum ALP at 2 weeks	1	40	Mean Difference (IV, Fixed, 95% CI)	‐36.35 [‐91.14, 18.44]
4.2 Serum ALP at 4 weeks	1	40	Mean Difference (IV, Fixed, 95% CI)	‐34.90 [‐81.23, 11.43]
4.3 Serum ALP at 6 weeks	1	40	Mean Difference (IV, Fixed, 95% CI)	‐56.85 [‐101.27, ‐12.43]
5 Osteopenia Show forest plot	1	40	Risk Ratio (M‐H, Fixed, 95% CI)	0.62 [0.33, 1.15]
Open in figure viewer Analysis 1.5 Comparison 1 Calcium supplementation versus no calcium supplementation, Outcome 5 Osteopenia.

Figure 1

Study flow diagram (2016).

Ir a la figura de la revisiónAbrir en una pestaña nueva

Figure 2

Risk of bias graph: review authors' judgements about each risk of bias item presented as percentages across all included studies.

Ir a la figura de la revisiónAbrir en una pestaña nueva

Figure 3

Risk of bias summary: review authors' judgements about each risk of bias item for each included study.

Ir a la figura de la revisiónAbrir en una pestaña nueva

Analysis 1.1

Comparison 1 Calcium supplementation versus no calcium supplementation, Outcome 1 Weight (g).

Ir a la figura de la revisiónAbrir en una pestaña nueva

Analysis 1.2

Comparison 1 Calcium supplementation versus no calcium supplementation, Outcome 2 Length (cm).

Ir a la figura de la revisiónAbrir en una pestaña nueva

Analysis 1.3

Comparison 1 Calcium supplementation versus no calcium supplementation, Outcome 3 Head circumference (cm).

Ir a la figura de la revisiónAbrir en una pestaña nueva

Analysis 1.4

Comparison 1 Calcium supplementation versus no calcium supplementation, Outcome 4 Serum alkaline phosphatase.

Ir a la figura de la revisiónAbrir en una pestaña nueva

Analysis 1.5

Comparison 1 Calcium supplementation versus no calcium supplementation, Outcome 5 Osteopenia.

Ir a la figura de la revisiónAbrir en una pestaña nueva

Summary of findings for the main comparison. Calcium supplementation compared with no calcium supplementation for preterm infants

Calcium supplementation compared with no calcium supplementation for preterm infants
Patient or population: preterm hospitalised infants Setting: hospital setting Intervention: calcium and/or phosphorus supplementation Comparison: no supplement
Outcomes	*Anticipated absolute effects (95% CI)**		Relative effect (95% CI)	Number of participants (studies)	Quality of the evidence (GRADE)	Comments
Outcomes	Risk with no calcium/phosphorus supplementation	Risk with calcium/phosphorus supplementation	Relative effect (95% CI)	Number of participants (studies)	Quality of the evidence (GRADE)	Comments
Weight (g) ‐ weight at 6 weeks	Mean weight (g) ‐ weight at 6 weeks was 2483 g	MD 138.5 g higher (82.16 lower to 359.16 higher)	‐	40 (1 RCT)	⊕⊕⊝⊝ Low^a,b
Length (cm) ‐ length at 6 weeks	Mean length (cm) ‐ length at 6 weeks was 47.04 cm	MD 0.77 cm higher (0.93 lower to 2.47 higher)	‐	40 (1 RCT)	⊕⊕⊝⊝ Low^a,c
Head circumference (cm) ‐ head circumference at 6 weeks	Mean head circumference (cm) ‐ head circumference at 6 weeks was 34.31 cm	MD 0.33 cm higher (0.3 lower to 0.96 higher)	‐	40 (1 RCT)	⊕⊕⊝⊝ Low^a,c
Bone fracture (neonatal) ‐ not measured	‐	‐	‐	‐	‐	This was not a prespecified outcome; included study did not report this outcome
Growth (childhood/adulthood) ‐ not measured	‐	‐	‐	‐	‐	Included study provided no follow‐up into childhood
Bone mineral density (infant/childhood/adulthood) ‐ not measured	‐	‐	‐	‐	‐	Included study provided no follow‐up into childhood
Fracture (childhood/adulthood) ‐ not measured	‐	‐	‐	‐	‐	Included study provided no follow‐up into childhood
*Risk in the intervention group (and its 95% confidence interval) is based on assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI) CI: confidence interval; OR: odds ratio; RR: risk ratio
GRADE Working Group grades of evidence High quality: We are very confident that the true effect lies close to the estimate of effect Moderate quality: We are moderately confident in the effect estimate: The true effect is likely to be close to the estimate of effect but may be substantially different Low quality: Our confidence in the effect estimate is limited: The true effect may be substantially different from the estimate of effect Very low quality: We have very little confidence in the effect estimate: The true effect is likely to be substantially different from the estimate of effect
^aRisk of bias: insufficient evidence to judge methods of randomisation, allocation concealment or blinding of personnel ‐ downgraded one level ^bImprecision: wide confidence intervals and data from a single small study ‐ downgraded one level ^cImprecision: evidence from a single small study ‐ downgraded one level

Summary of findings for the main comparison. Calcium supplementation compared with no calcium supplementation for preterm infants

Ir a la tabla de la revisión

Comparison 1. Calcium supplementation versus no calcium supplementation

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Weight (g) Show forest plot	1		Mean Difference (IV, Fixed, 95% CI)	Subtotals only

1.1 Weight at 2 weeks	1	40	Mean Difference (IV, Fixed, 95% CI)	52.5 [‐155.44, 260.44]
1.2 Weight at 4 weeks	1	40	Mean Difference (IV, Fixed, 95% CI)	60.00 [‐151.39, 271.39]
1.3 Weight at 6 weeks	1	40	Mean Difference (IV, Fixed, 95% CI)	138.5 [‐82.16, 359.16]
2 Length (cm) Show forest plot	1		Mean Difference (IV, Fixed, 95% CI)	Subtotals only

2.1 Length at 2 weeks	1	40	Mean Difference (IV, Fixed, 95% CI)	0.34 [‐1.36, 2.04]
2.2 Length at 4 weeks	1	40	Mean Difference (IV, Fixed, 95% CI)	0.47 [‐1.20, 2.14]
2.3 Length at 6 weeks	1	40	Mean Difference (IV, Fixed, 95% CI)	0.77 [‐0.93, 2.47]
3 Head circumference (cm) Show forest plot	1		Mean Difference (IV, Fixed, 95% CI)	Subtotals only

3.1 Head circumference at 2 weeks	1	40	Mean Difference (IV, Fixed, 95% CI)	0.19 [‐0.42, 0.80]
3.2 Head circumference at 4 weeks	1	40	Mean Difference (IV, Fixed, 95% CI)	0.22 [‐0.39, 0.83]
3.3 Head circumference at 6 weeks	1	40	Mean Difference (IV, Fixed, 95% CI)	0.33 [‐0.30, 0.96]
4 Serum alkaline phosphatase Show forest plot	1		Mean Difference (IV, Fixed, 95% CI)	Subtotals only

4.1 Serum ALP at 2 weeks	1	40	Mean Difference (IV, Fixed, 95% CI)	‐36.35 [‐91.14, 18.44]
4.2 Serum ALP at 4 weeks	1	40	Mean Difference (IV, Fixed, 95% CI)	‐34.90 [‐81.23, 11.43]
4.3 Serum ALP at 6 weeks	1	40	Mean Difference (IV, Fixed, 95% CI)	‐56.85 [‐101.27, ‐12.43]
5 Osteopenia Show forest plot	1	40	Risk Ratio (M‐H, Fixed, 95% CI)	0.62 [0.33, 1.15]

Comparison 1. Calcium supplementation versus no calcium supplementation

Ir a la tabla de la revisión

	Idioma de la Revisión Cochrane Escoja su idioma de preferencia para las revisiones Cochrane y otros contenidos. Las secciones sin una traducción aparecerán en inglés.

	Idioma de la web Escoja su idioma de preferencia para la web de la Biblioteca Cochrane.

Idioma de la Revisión Cochrane

Idioma de la web

Referencias

References to studies included in this review

Torabi 2014 {published data only}

References to studies excluded from this review

Atkinson 1989 {published and unpublished data}

Carroll 2011 {published data only}

Faerk 2000 {published data only}

Greer 1988 {published and unpublished data}

Gross 1987 {published data only}

Gupta (unpublished data) {unpublished data only}

Hall 1993 {published data only}

Lucas 1996 {published and unpublished data}

Salle 1986 {published data only}

Sann 1985 {published data only}

Schanler 1988 {published data only}

Senterre 1983 {published data only}

References to studies awaiting assessment

Boehm 1988 {published data only}

Kamali 2014 {published data only}

Additional references

American Academy of Pediatrics 2014

Atkinson 1983

Bhatia 2007

Bozzetti 2009

Brown 2016

GradePro GDT [Computer program]

Guyatt 2011a

Guyatt 2011b

Guyatt 2011c

Guyatt 2011d

Guyatt 2011e

Higgins 2011

Itani 1991

Kuschel 1998

Review Manager 2013 [Computer program]

Rowe 1979

Rowe 1984

Schell‐Feith 2010

Schünemann 2013

Winsloe 2009

References to other published versions of this review

Kuschel 2001

Characteristics of studies

Characteristics of included studies [ordered by study ID]

Characteristics of excluded studies [ordered by study ID]

Characteristics of studies awaiting assessment [ordered by study ID]

Data and analyses

Copiar o descargar referencia

Idioma de la Revisión Cochrane

Idioma de la web

Instituciones a las que se accedió previamente

Usuarios institucionales

Instituciones a las que se accedió previamente

Otras opciones de acceso