Thyroid as an adjuvant to amphetamine therapy of obesity. A controlled double-blind study

Lifestyle treatments in randomized clinical trials of pharmacotherapies for obesity

OBJECTIVE

This meta-analysis evaluated the types of lifestyle treatments used in published obesity drug studies and assessed their contribution to weight losses associated with pharmacological interventions.

RESEARCH METHODS AND PROCEDURES

Randomized, placebo-controlled, double-blind clinical trials of anti-obesity agents that are/were Food and Drug Administration-approved for the treatment of obesity (both prescription and over-the-counter), and drugs that are Food and Drug Administration-approved and are used off-label for obesity were included. Studies were located by computer searches of databases (e.g., Medline, PsychInfo) and reviewing tables of content/reference sections of journals, abstracts, previous reviews, past empirical studies, relevant book chapters, and recent issues of journals that regularly publish obesity research. In addition, a number of individuals who regularly publish in the obesity literature were asked to provide personal lists of obesity-drug studies. Based on the above criteria, a total of 108 randomized clinical trials were located.

RESULTS

Balanced-deficit diets, low-calorie diets, and self-monitoring were the most used lifestyle treatments in published obesity studies. They were incorporated into 40.7%, 25%, and 23.1% of pharmacotherapy studies, respectively. Physical activity and other behavioral or psychotherapeutic interventions rarely were used. A substantial portion of weight loss experienced by patients was attributable to both "placebo effects" and to the lifestyle treatments.

DISCUSSION

Obesity-pharmacotherapy trials do not use lifestyle treatments with the frequency expected based on the official positions of most professional organizations concerned with the comprehensive management of obesity.

Effect of 'physiological' doses of triiodothyronine replacement on the hormonal and metabolic adaptation to short-term semistarvation and to low-calorie diet in obese patients

In four groups of obese patients matched for Body Mass Index (BMI), we studied the effects of different 3-week semi-starvation treatments followed by an 8-week hypocaloric (1008 kcal, protein 20%, carbohydrate 40%) diet with or without low doses of T3 therapy. Dietary intake (formula diet) in the semi-starvation period was 480 kcal, with 66 g protein (P) and 51 g carbohydrate (CHO) in groups I and III and with 33 g P and 84 g CHO in groups II and IV. Moreover, groups III and IV were given low doses (20 micrograms twice a day) of T3 while groups I and II received a placebo. During semi-starvation periods, a similar fall in BMI values was found in all groups, while during the low-calorie diet, T3-treated patients showed the greater BMI reduction. During semi-starvation, nitrogen balance was significantly more negative in low-protein than in high-protein-treated groups; differences between T3-treated (III and IV) and control (I and II) groups were not significant over this relatively short treatment period. No differences in 24 h urinary 3-methylhistidine or alanine excretion were evident between the four groups. During the entire period of study, daily urine creatinine excretion did not change in any group. In conclusion, in our study low-dose T3 therapy was seen to favour weight loss during low-calorie diet although negative effects on protein metabolism were not excluded, particularly when relatively small amounts of protein were administered.

Treatment of obesity with triiodothyronine and a very-low-calorie liquid formula diet

In a double-blind trial physiological doses (60 microgram/day) of triiodothyronine (T3) were compared with placebo in a group of obese patients on a 320 kcal/day (1.34 MJ) liquid formula diet. T3-treated patients had a significantly greater weight-loss by the 12th week. Analysis of serum levels of T3 and thyroxine (T4) showed that those patients in the placebo group whose weight-loss tended to level off at a plateau towards the end of the trial also had the lowest T3 levels and resting metabolic rate (RMR) at that time. Patients in the T3 group had a steady rise in serum T3 levels during the 12 wk period. Those with the highest final T3 levels had the greatest tendency for their weight-loss to level out and, paradoxically, had the least suppression of serum T4 levels and lowest RMR. Some obese patients who do not readily lose weight on conventional low-calorie diets may have an impaired metabolic clearance rate of T3 and a degree of T3 resistance.

Pharmacological approaches to treating the obese patient

It should be obvious from the foregoing discussion that, at the present time, there is not an acceptably safe and effective pharmacological treatment for obesity. This patent inadequacy of present drug regimens has spawned the investigation into the diverse pharmacological approaches reviewed in this paper as well as investigation into the intestinal bypass operation (see Chapter 10). We feel that the eventual, safe and effective therapy for obesity will come from the pharmacological realm. Glucose-blocking drugs, growth hormone analogues, and hydroxycitrate are but three of the potentially safe and effective approaches to the problem for the future. It will be truly fascinating to watch the development in the treatment of obesity and, specifically, the pharmacological treatment for this problem over the next five to ten years.

Nerve regeneration and thyroid hormone treatment

On the basis of 3 reports that thyroid hormone treatment stimulates axon outgrowth in rats with nervous system injuries, a 43-year-old patient with an ulnar nerve laceration was given desiccated thyroid (up to 360 mg/day) following nerve suture. The Hoffmann-Tinel sign of sensory axon outgrowth advanced at a rate of 5.0 mm/day in the forearm, approximately 200% faster than the anticipated rate. A good functional result was obtained in 7 months. On the maximum dosage of desiccated thyroid, the patient developed mild weight loss associated with an increased appetite; there was no other sign or symptom of hyperthyroidism. Further investigation of the role of thyroid hormone during nerve regeneration seems warranted.