Interventions to prevent women from developing gestational diabetes mellitus: an overview of Cochrane Reviews.

BACKGROUND: The prevalence of gestational diabetes mellitus (GDM) is increasing, with approximately 15% of pregnant women affected worldwide, varying by country, ethnicity and diagnostic thresholds. There are associated short- and long-term health risks for women and their babies. OBJECTIVES: We aimed to summarise the evidence from Cochrane systematic reviews on the effects of interventions for preventing GDM. METHODS: We searched the Cochrane Database of Systematic Reviews (6 August 2019) with key words 'gestational diabetes' OR 'GDM' to identify reviews pre-specifying GDM as an outcome. We included reviews of interventions in women who were pregnant or planning a pregnancy, irrespective of their GDM risk status. Two overview authors independently assessed eligibility, extracted data and assessed quality of evidence using ROBIS and GRADE tools. We assigned interventions to categories with graphic icons to classify the effectiveness of interventions as: clear evidence of benefit or harm (GRADE moderate- or high-quality evidence with a confidence interval (CI) that did not cross the line of no effect); clear evidence of no effect or equivalence (GRADE moderate- or high-quality evidence with a narrow CI crossing the line of no effect); possible benefit or harm (low-quality evidence with a CI that did not cross the line of no effect or GRADE moderate- or high-quality evidence with a wide CI); or unknown benefit or harm (GRADE low-quality evidence with a wide CI or very low-quality evidence). MAIN RESULTS: We included 11 Cochrane Reviews (71 trials, 23,154 women) with data on GDM. Nine additional reviews pre-specified GDM as an outcome, but did not identify GDM data in included trials. Ten of the 11 reviews were judged to be at low risk of bias and one review at unclear risk of bias. Interventions assessed included diet, exercise, a combination of diet and exercise, dietary supplements, pharmaceuticals, and management of other health problems in pregnancy. The quality of evidence ranged from high to very low. Diet Unknown benefit or harm: there was unknown benefit or harm of dietary advice versus standard care, on the risk of GDM: risk ratio (RR) 0.60, 95% CI 0.35 to 1.04; 5 trials; 1279 women; very low-quality evidence. There was unknown benefit or harm of a low glycaemic index diet versus a moderate-high glycaemic index diet on the risk of GDM: RR 0.91, 95% CI 0.63 to 1.31; 4 trials; 912 women; low-quality evidence. Exercise Unknown benefit or harm: there was unknown benefit or harm for exercise interventions versus standard antenatal care on the risk of GDM: RR 1.10, 95% CI 0.66 to 1.84; 3 trials; 826 women; low-quality evidence. Diet and exercise combined Possible benefit: combined diet and exercise interventions during pregnancy versus standard care possibly reduced the risk of GDM: RR 0.85, 95% CI 0.71 to 1.01; 19 trials; 6633 women; moderate-quality evidence. Dietary supplements Clear evidence of no effect: omega-3 fatty acid supplementation versus none in pregnancy had no effect on the risk of GDM: RR 1.02, 95% CI 0.83 to 1.26; 12 trials; 5235 women; high-quality evidence. Possible benefit: myo-inositol supplementation during pregnancy versus control possibly reduced the risk of GDM: RR 0.43, 95% CI 0.29 to 0.64; 3 trials; 502 women; low-quality evidence. Possible benefit: vitamin D supplementation versus placebo or control in pregnancy possibly reduced the risk of GDM: RR 0.51, 95% CI 0.27 to 0.97; 4 trials; 446 women; low-quality evidence. Unknown benefit or harm: there was unknown benefit or harm of probiotic with dietary intervention versus placebo with dietary intervention (RR 0.37, 95% CI 0.15 to 0.89; 1 trial; 114 women; very low-quality evidence), or probiotic with dietary intervention versus control (RR 0.38, 95% CI 0.16 to 0.92; 1 trial; 111 women; very low-quality evidence) on the risk of GDM. There was unknown benefit or harm of vitamin D + calcium supplementation versus placebo (RR 0.33, 95% CI 0.01 to 7.84; 1 trial; 54 women; very low-quality evidence) or vitamin D + calcium + other minerals versus calcium + other minerals (RR 0.42, 95% CI 0.10 to 1.73; 1 trial; 1298 women; very low-quality evidence) on the risk of GDM. Pharmaceutical Possible benefit: metformin versus placebo given to obese pregnant women possibly reduced the risk of GDM: RR 0.85, 95% CI 0.61 to 1.19; 3 trials; 892 women; moderate-quality evidence. Unknown benefit or harm:eight small trials with low- to very low-quality evidence showed unknown benefit or harm for heparin, aspirin, leukocyte immunisation or IgG given to women with a previous stillbirth on the risk of GDM. Management of other health issues Clear evidence of no effect: universal versus risk based screening of pregnant women for thyroid dysfunction had no effect on the risk of GDM: RR 0.93, 95% CI 0.70 to 1.25; 1 trial; 4516 women; moderate-quality evidence. Unknown benefit or harm: there was unknown benefit or harm of using fractional exhaled nitrogen oxide versus a clinical algorithm to adjust asthma therapy on the risk of GDM: RR 0.74, 95% CI 0.31 to 1.77; 1 trial; 210 women; low-quality evidence. There was unknown benefit or harm of pharmacist led multidisciplinary approach to management of maternal asthma versus standard care on the risk of GDM: RR 5.00, 95% CI 0.25 to 99.82; 1 trial; 58 women; low-quality evidence. AUTHORS' CONCLUSIONS: No interventions to prevent GDM in 11 systematic reviews were of clear benefit or harm. A combination of exercise and diet, supplementation with myo-inositol, supplementation with vitamin D and metformin were of possible benefit in reducing the risk of GDM, but further high-quality evidence is needed. Omega-3-fatty acid supplementation and universal screening for thyroid dysfunction did not alter the risk of GDM. There was insufficient high-quality evidence to establish the effect on the risk of GDM of diet or exercise alone, probiotics, vitamin D with calcium or other vitamins and minerals, interventions in pregnancy after a previous stillbirth, and different asthma management strategies in pregnancy. There is a lack of trials investigating the effect of interventions prior to or between pregnancies on risk of GDM.

Vapocoolants (cold spray) for pain treatment during intravenous cannulation.

BACKGROUND: Intravenous cannulation is a painful procedure that can provoke anxiety and stress. Injecting local anaesthetic can provide analgesia at the time of cannulation, but it is a painful procedure. Topical anaesthetic creams take between 30 and 90 minutes to produce an effect. A quicker acting analgesic allows more timely investigation and treatment. Vapocoolants have been used in this setting, but studies have reported mixed results. OBJECTIVES: To determine effects of vapocoolants on pain associated with intravenous cannulation in adults and children. To explore variables that might affect the performance of vapocoolants, including time required for application, distance from the skin when applied and time to cannulation. To look at adverse effects associated with the use of vapocoolants. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, Latin American Caribbean Health Sciences Literature (LILACS), the Cumulative Index to Nursing and Allied Health Literature (CINAHL), the Institute for Scientific Information (ISI) Web of Science and the http://clinicaltrials.gov/, http://www.controlled-trials.com/ and http://www.trialscentral.org/ databases to 1 May 2015. We applied no language restrictions. We also scanned the reference lists of included papers. SELECTION CRITERIA: We included all blinded and unblinded randomized controlled trials (RTCs) comparing any vapocoolant with placebo or control to reduce pain during intravenous cannulation in adults and children. DATA COLLECTION AND ANALYSIS: Three review authors independently assessed trial quality and extracted data, contacted study authors for additional information and assessed included studies for risk of bias. We collected and analysed data for the primary outcome of pain during cannulation, and for the secondary outcomes of pain associated with application of the vapocoolant, first attempt success rate of intravenous cannulation, adverse events and participant satisfaction. We performed subgroup analyses for the primary outcome to examine differences based on age of participant, type of vapocoolant used, application time of vapocoolant and clinical situation (emergency vs elective). We used random-effects model meta-analysis in RevMan 5.3 and assessed heterogeneity between trial results by examining forest plots and calculating the I(2) statistic. MAIN RESULTS: We found nine suitable studies of 1070 participants and included them in the qualitative analyses. We included eight studies of 848 participants in the meta-analysis for the primary outcome (pain during intravenous cannulation). Use of vapocoolants resulted in a reduction in pain scores as measured by a linear 100 mm visual analogue scale (VAS 100) compared with controls (difference between means -12.5 mm, 95% confidence interval (CI) -18.7 to -6.4 mm; moderate-quality evidence). We could not include in the meta-analysis one study, which showed no effects of the intervention.Use of vapocoolants resulted in increased pain scores at the time of application as measured by a VAS 100 compared with controls (difference between means 6.3 mm, 95% CI 2.2 to 10.3 mm; four studies, 461 participants; high-quality evidence) and led to no difference in first attempt success compared with controls (risk ratio (RR) 1.00, 95% CI 0.94 to 1.06; six studies, 812 participants; moderate-quality evidence). We documented eight minor adverse events reported in 279 vapocoolant participants (risk difference (RD) 0.03, 95% CI 0 to 0.05; five studies, 551 participants; low quality-evidence).The overall risk of bias of individual studies ranged from low to high, with high risk of bias for performance and detection bias in four studies. Sensitivity analysis showed that exclusion of studies at high or unclear risk of bias did not materially alter the results of this review. AUTHORS' CONCLUSIONS: Moderate-quality evidence indicates that use of a vapocoolant immediately before intravenous cannulation reduces pain during the procedure. Use of vapocoolant does not increase the difficulty of cannulation nor cause serious adverse effects but is associated with mild discomfort during application.