Anti-obesity drugs

At this time when there is a sudden upsurge of interest in obesity it seemed timely to précis a recent Bandolier review of the topic.

The short answer is that in long term studies of a year or more, people taking these drugs achieved a weight loss of 3-4% more than doing nothing.

A systematic review looking only at double blind, randomised trials of at least one year were accepted. They had to enroll patients with a BMI of at least 30 kg/sq metre, and have a placebo or active control. Full, published studies in any language were accepted.

Only 11 studies of orlistat (6,021 participants) and three of sibutramine (929 participants) met the inclusion criteria.

Orlistat 120 mg three times a day for a year or more produced a consistent reduction in weight above that of placebo by an average of 2.7 kg or 2.9% of initial weight. Compared with placebo 21% of patients (NNT 5) had at least a 5% weight loss and 12% (NNT 10) achieved a 10% weight loss.

Sibutramine 15-20 mg daily for a year or more produced a consistent reduction in weight above that of placebo by an average of 4.3 kg or 4.6% of initial weight. Compared with placebo 34% of patients (NNT 3) had at least a 5% weight loss and 15% (NNT 7) achieved a 10% weight loss.

Gastrointestinal adverse events predominated with orlistat, and included fatty or oily stool, faecal urgency, and oily spotting in 15% to 30% of patients. Faecal incontinence occurred in 7% of those on orlistat compared with 1% on placebo, a number needed to harm of 17.

Sibutramine adverse events included increases in systolic and diastolic blood pressure of 1-3 mmHg, and pulse rate increases of 4-5 beats per minute. Other adverse events such as insomnia, dry mouth, nausea and constipation occurred in 7-20%

Overall a minority of patients achieved a 10% or greater weight loss, which is a useful amount. The authors of the review comment that there were no predictive factors for responders, and suggested that therapeutic trials made sense because many patients would stop because of adverse events, while the near maximal weight loss was usually seen in the individual studies by six months. The bottom line is that weight reducing drugs are of value in a few, with significant adverse events in many.

Ref: Web

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Importance of hospital high volumes

Evidence that the short term outcomes of complex surgical procedures are better in hospitals that do high volumes of such procedures has prompted some authors to suggest that all high risk surgery should be regionalised at high volume hospitals. 

Health policy measures advocating volume based regionalisation are predicated on the assumption that the high volume is specific to the volume of the same procedure.

This study in the BMJ was undertaken to determine whether the improved outcome of complex surgery is related to the volume of that specific surgical procedure.

This study was an analysis of secondary data in Ontario, Canada, looking at patients having an oesophagectomy, colorectal resection for cancer, pancreaticduodenectomy, major lung resection for cancer, or repair of an unruptured abdominal aortic aneurysm between 1994 and 1999.

The main outcome measures were odds ratio for death within 30 days of surgery in relation to the hospital volume of the same surgical procedure and the hospital volume of the other four procedures.  Estimates were adjusted for age, sex, and co-morbidity and accounted for hospital level clustering.

With the exception of colorectal resection, the 30 day mortality seemed to be inversely related not only to the hospital volume of the same procedure but also to the hospital volume of most of the other procedures.  In some cases the effect of the volume of a different procedure was stronger than the effect of the volume of the same procedure. 

For example, the association of mortality from pancreaticoduodenectomy with hospital volume of lung resection (odds ratio for death in hospitals with a high volume of lung resection compared with low volume 0.36, 95% confidence interval 0.23 to 0.57) was much stronger than the association of mortality from pancreaticoduodenectomy with hospital volume of pancreaticoduodenectomy (0.76, 0.44 to 1.32). 

The authors conclude that the inverse association between high volume of procedure and risk of operative death is not specific to the volume of the procedure being studied.

Ref: Web

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Management of bedwetting in children

Bedwetting (nocturnal enuresis) is common among school-aged children, with around one in six 5 year olds, and at least one in fifty 7 year old boys and one in a hundred 7 year old girls, wetting the bed more than once a week. 

Star charts and reward systems

A systematic review included two randomised-controlled trials and one in which the children were allocated alternately to star charts or to no treatment (in a total of 127 children).  The review found that star charts were associated with fewer wet nights than was no treatment, and more longer-term success after treatment stopped.

Star charts and tangible reward systems need to reward specific behaviours the child can control (e.g. getting out of bed when they wake and then using the toilet) rather than achieving ‘a dry bed’. 

Enuresis alarms

A systematic review, including 53 randomised controlled  trials involving a total of 2,862 children, found that around two-thirds of children became dry with an alarm (relative risk [RR] for failure vs. no treatment 0.36, 95% CI 0.31-0.43). 

Also, 45% of children who used the alarms remained dry after treatment finished (up to 20 weeks’ treatment, followed by up to 12 months’ observation), compared with 1% of children receiving no treatment (RR for failure or relapse 0.56, 95% CI 0.46-0.68, number needed to treat [NNT] 2). 

There is evidence to suggest that body-worn alarms may have a quicker effect than bed alarms. 

Once contributory factors have been ruled out or addressed, treatment may be started.  Simple behavioural methods such as star charts and reward systems are often tried initially and may be effective, although the published evidence on these approaches is weak. 

Enuresis alarms can be effective and can be used by well-motivated families.  Complex behavioural interventions, including dry bed training, can be effective but are demanding.

Ref Drugs & Therapeutics Bulletin May 2004

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