Efficacy of Metformin Treatment with Respect to Weight Reduction in Children and Adults with Obesity: A Systematic Review

BACKGROUND

Obesity and its related complications are increasing health issues. Since generally only minor weight loss is obtained with lifestyle intervention, additional pharmacological therapies such as metformin are often used.

OBJECTIVE

We conducted a systematic review to provide an overview of the efficacy of ≥ 6 months of metformin treatment in children and adults with respect to weight, insulin resistance, and progression toward type 2 diabetes mellitus (T2DM).

METHODS

In September 2018, we searched PubMed, Embase, and the Cochrane Library for studies published in English using the keywords metformin, obesity/overweight, and weight loss. Prospective studies reporting weight/body mass index (BMI) as a primary or secondary outcome in patients with overweight/obesity with ≥ 6 months' metformin treatment were included. Included subjects were children and adults with overweight/obesity who received ≥ 6 months of metformin and/or lifestyle intervention, and/or placebo and/or lifestyle intervention, and/or standard care. Studies were independently screened by two reviewers. Data were extracted by one and verified by the other reviewer, and both reviewers assessed the risk of bias using the Cochrane risk-of-bias tool.

RESULTS

Our review includes 15 pediatric and 14 adult studies. In children, after 6 months, more than half the studies reported a greater reduction in BMI with metformin versus controls. Only six studies had an intervention of > 6 months, and these studies found no further improvement in BMI in the metformin users, though their BMI was lower than that of controls. Three studies showed a significant improvement in insulin sensitivity in the metformin versus the control group. Adults using metformin experienced and maintained small decreases in weight irrespective of duration of intervention. In 11 of 14 studies, a greater reduction in weight/BMI was observed with metformin than with placebo. Progression toward T2DM was significantly reduced in adults using metformin, ranging from 7 to 31%. The safety and tolerability of metformin, withdrawal of participants, and comparison with other drugs were not taken into account.

CONCLUSIONS

The effects of metformin on weight/BMI vary, with smaller reductions in children than in adults. This could be because of differences in adherence, daily dosage, and insulin status. Metformin significantly reduced the progression toward T2DM in adults. Therefore, metformin should be considered as a treatment for obesity and its related complications.

Asthma medication in children who are overweight/obese: justified treatment?

BACKGROUND

The prevalence of asthma and obesity have increased over the last decades. A possible association between these two chronic illnesses has been suggested, since the prevalence of asthmatic symptoms rises with increasing Body Mass Index (BMI). However, asthma is only one of several possible causes of shortness of breath in obese children. The aim of this study is to evaluate the prevalence of overtreatment with asthma medication in a cohort overweight/obese children with respiratory symptoms visiting a pediatric outpatient clinic.

METHODS

Children referred to a pediatric outpatient clinic aged ≥4- ≤ 18 years with overweight/obesity (defined as BMI-sds > 1.1) and asthmatic symptoms were included. The diagnosis asthma was evaluated and classified in no, unlikely, probable and confirmed asthma, based on clinical parameters and/or spirometry results. Overtreatment was defined as asthma medication prescribed in participants classified as no or unlikely asthma. And undertreatment as probable or confirmed asthma without asthma medication prescribed .

RESULTS

Three hundred thirty-eight participants were included, of which 92.6% (313/338) had a prescription for asthma medication. Overtreatment was observed in 27.2% (92/338) participants. Nine participants were undertreated.

CONCLUSION

More than 25% overtreatment with asthma medication was observed in a cohort overweight/obese children with asthmatic symptoms. This finding emphasizes that the diagnosis of asthma must be confirmed before commencement of medication. The diagnosis of asthma should be based on standard questionnaires evaluating asthmatic symptoms, lung functions test and regular reassessments. Further studies concerning overtreatment with asthma medication in normal weight pediatric populations are warranted, to evaluate whether overtreatment is specific for overweight/obese children.

Increased Arterial Stiffness in Adolescents With Obesity

Increased arterial stiffness (AS) is an early sign of cardiovascular disease. Influence of weight, puberty, and insulin resistance (IR) on AS in adolescents is unclear. Therefore, this study compared AS, assessed with pulse wave velocity (PWV) and augmentation index (AIx), of adolescents with and without obesity and evaluated the influence of puberty and IR on AS. Sixty-two lean and 61 adolescents with obesity were included. Significantly higher PWV was observed in adolescents with obesity (4.1 ms⁻¹ [2.4 to 5.6 ms⁻¹] vs 3.6 ms⁻¹ [0.4 to 6.1 ms⁻¹]; P = .01), while AIx was not significant different. However, significantly higher AIx was observed in adolescents with obesity and IR (3.0 [−17.5% to 28.5%] vs −3.0 [−19.0% to 13.0%]; P = .01). For Tanner stages, no differences were observed. The higher PWV in adolescents with obesity and higher AIx in adolescents with obesity and IR both indicate an increased AS. Consequently, measurement of AS should be considered in adolescents with obesity and IR as part of cardiovascular risk assessment.

Skin autofluorescence in children with and without obesity

Background Obesity is associated with oxidative stress, which is related to increased advanced glycation end product (AGE) formation. AGEs accumulated in skin collagen can be measured with skin autofluorescence (sAF). There are conflicting reports on the influence of obesity on sAF in adults and no data in children. Therefore, this study evaluated sAF in pediatric patients with and without obesity. Methods In this cross-sectional study, participants aged 4-18 years were included: patients with obesity (body mass index standard deviation score [BMI-SDS] >2.3) and lean controls (BMI-SDS >-1.1 to <1.1). sAF was measured using the AGE Reader®. Participants were stratified according to age (<10, ≥10 to <13, ≥13 to <15, ≥15 to <17 and ≥17 years) and skin type (I-VI). Results In total, 143 patients and 428 controls were included. In patients, there was no influence of age on sAF (p=0.09). In controls, sAF was higher in children aged <10 years compared to ≥10 to <13 and ≥13 to <15 years (p=0.02; p=0.04). Stratified by age, sAF was higher in patients compared to controls in all age categories, except <10 years of age (p<0.01), while this was not observed when stratified by skin type (p>0.05). Skin type and BMI were significant covariates for sAF. Conclusions BMI was a covariate for sAF; however, no difference in sAF was observed between children with and without obesity, stratified by skin type. Duration of obesity as well as accuracy of the AGE Reader® might explain this difference. Further research is warranted, in which patients should be matched for age and skin type.

Psychostimulants: Influence on Body Mass Index and Height in a Pediatric Population with Attention-Deficit/Hyperactivity Disorder?

OBJECTIVES

Attention-deficit/hyperactivity disorder (ADHD) is often treated with psychostimulants. Psychostimulants' adverse effects on body mass index standard deviation score (BMI-sds) and height in children/adolescents with ADHD have been reported. However, literature is inconsistent, and it is unclear whether the observed effects are dosage- and/or BMI-dependent. Therefore, the aim of this retrospective observational study is to evaluate the influence of psychostimulants on BMI-sds and height-sds in a pediatric cohort with ADHD from an outpatient clinic, and to study the correlation between psychostimulant dosage and BMI-sds and height-sds change.

METHOD

Participants ≤18 years of age diagnosed with ADHD who started with psychostimulants (methylphenidate) were studied. Changes in BMI-sds and height-sds over an 18-month treatment period were assessed in subgroups according to baseline BMI-sds, gender, and age. Furthermore, correlations between BMI-sds, height-sds, and psychostimulant dose were studied.

RESULTS

In total, 298 participants [median age 9.8 years, height-sds 0.0, BMI-sds 0.5, psychostimulant dosage 0.5 (0.2-1.4) mg/kg/day] were analyzed, with an underweight, overweight, and obesity prevalence of 5%, 21%, and 7%, respectively. After 18 months of treatment a significant decline in BMI-sds (-0.4) and height-sds (-0.2) was observed. These effects were consistent in all subgroups except for no change in BMI-sds in the underweight subgroup and no change in height-sds in the overweight subgroup. Medication dosage was weakly correlated with change in BMI-sds [r = -0.3 (-0.9 to +0.5); p < 0.01] and height-sds [r = -0.2 (-0.4 to -0.1); p = 0.01].

CONCLUSION

After 18 months of psychostimulant treatment, a significant decline in BMI-sds and height-sds was observed. However, the correlation with psychostimulant dosage was weak, and the decline was not observed in all subgroups. Therefore, further studies on the etiology of BMI-change are warranted, particularly with regard to the ADHD symptoms.

Predictors of Insulin Resistance in Children versus Adolescents with Obesity

INTRODUCTION

Obesity is a risk factor to develop metabolic syndrome (MetS) and type 2 diabetes mellitus (T2DM). Insulin resistance (IR) plays a major part in both. With increasing incidence of childhood obesity, this retrospective study aimed to identify predictors of IR in children/adolescents with obesity to optimize screening for IR.

METHOD

Patients aged ≥ 2-≤ 18 years with obesity (BMI-SDS > 2.3) were included. IR was defined as HOMA-IR ≥ 3.4, and MetS if ≥3 of the following criteria were present: waist circumference and blood pressure ≥ 95th age percentile, triglycerides ≥ 1.7 mmol/l, HDL < 1.03 mmol/l, and fasting plasma glucose ≥ 5.6 mmol/l.

RESULTS

In total, 777 patients were included. Of the 306 children, 51, 38, and 0 were diagnosed with IR, MetS, and T2DM, respectively. Of the 471 adolescents, 223, 95, and 0 were diagnosed with IR, MetS, and T2DM, respectively. In the multivariable regression model, BMI-SDS, preterm birth, and Tanner stage were associated with IR in children (6.3 (95% CI 1.3-31.1), 5.4 (95% CI 1.4-20.5), 2.2 (95% CI 1.0-4.8)), and BMI-SDS and waist circumference in adolescents (4.0 (95% CI 1.7-9.2), 3.7 (95% CI 1.5-9.4)).

CONCLUSION

Different IR predictors were observed in children/adolescents with obesity. These predictors can be used to optimize screening for IR in pediatric populations.

Faecal gas analysis by electronic nose as novel, non-invasive method for assessment of active and quiescent paediatric inflammatory bowel disease: Proof of principle study

BACKGROUND AND AIMS

Inflammatory bowel disease (IBD) and its two phenotypes ulcerative colitis (UC) and Crohn's disease (CD) are essentially assessed by endoscopy, both in initial diagnostic work-up and during follow-up. This carries a high burden, especially on paediatric patients. Faecal volatile organic compounds (VOCs) are considered potential non-invasive biomarkers for intestinal diseases linked to gut microbiota alterations. We hypothesized that faecal VOC analysis by electronic nose allows discrimination of children with CD, UC and controls during active disease and remission.

METHODS

Faecal VOC patterns of children with newly diagnosed IBD and controls were studied by an electronic nose (Cyranose 320®), at baseline and upon achieving remission at 6-weeks of follow-up. Disease activity was assessed by global physician's assessment, substantiated by serum C-reactive protein and faecal calprotectin. Internally cross-validated receiver-operator-characteristic curves and corresponding sensitivity and specificity for detection of IBD were calculated RESULTS: Faecal VOC profiles of patients with UC (26) and CD (29) differed from controls (28); in active disease (AUC±95% CI, p-value, sensitivity, specificity: 1.00±0.00; p<0.001, 100%, 100%) and (0.85±0.05, p<0.001, 86%, 67%) and in clinical remission (0.94±0.06, p<0.001, 94%, 94%) and (0.94±0.06, p<0.001, 94%, 94%), respectively. Furthermore, CD-patients differed from UC-patients during active disease (0.96±0.03; p<0.001, 97%, 92%), and upon achieving clinical remission (0.81±0.08, p=0.002, 88%, 72%).

CONCLUSION

Faecal VOC analysis allowed discrimination of paediatric patients with IBD from controls, both during active disease and remission. It therefore has potential as non-invasive test, in both diagnostic work-up and assessment of disease activity in IBD.