Antidepressant use linked to increased weight gain

 

Taking antidepressants appears associated with weight gain in a recent study, though the researchers caution that the link might not be causal. Antidepressant use already was lowest in those with an initially normal BMI, and it increased with each category of greater BMI.

“Participants of normal weight showed an increased risk of transitioning to overweight or obesity, and overweight participants were more likely to become obese if they were treated with an antidepressant,” Rafael Gafoor, PhD, of King’s College London, and his associates wrote in BMJ.

“The risk of weight gain was substantially increased during the second and third years of treatment,” they reported. “The risk of weight gain remained increased during at least 6 years of follow-up.”

The researchers retrospectively analyzed EHRs from the U.K. Clinical Practice Research Datalink, representing about 7% of general practices in the United Kingdom, to compare the risk of weight gain among those who were and were not prescribed antidepressants. Of more than 2 million registered participants, a random sample of those with at least three measurements for body mass index (BMI), representing different weight classes, were included.

Out of 136,762 men and 157,957 women, 13% of the men and 22.4% of the women received prescriptions for antidepressants. The 10-year follow-up period included more than 1.8 million person-years. The proportion of people gaining at least 5% in BMI was 11.1% in those with antidepressants prescriptions, compared with 8.1% in those not prescribed antidepressants.

“Antidepressant use was greater in patients with comorbidity and coprescriptions, particularly with diagnoses of stroke and diabetes or coprescribing of antiepileptics or antipsychotics, than in those without,” the researchers wrote. “Antidepressant use was also associated with current smoking and higher deprivation category.”

The researchers adjusted the analysis to account for age, sex, initial BMI classification, smoking, prescriptions for antiepileptics or antipsychotics, year, region of residence, socioeconomic status, or having received advice on weight management or diet. They also accounted for diabetes, coronary heart disease, stroke, cancer, and depression diagnoses, and they eliminated the 280 days before a newborn delivery to account for pregnancy-related weight increases.

 

After adjustment for those potential confounders, people prescribed antidepressants were 21% more likely to experience substantial weight gain than those not prescribed them (adjusted rate ratio = 1.21; P less than .001). The researchers, cautioned, however, that residual confounding might have inflated the risk.

Those who had a normal weight when they began taking antidepressants had 29% greater risk of gaining enough weight to meet the criteria for overweight or obesity. Likewise, those already overweight when first prescribed antidepressants were 29% more likely to develop obesity.

For every 27 patients who took antidepressants for at least 1 year, 1 of them gained at least 5% in BMI during the subsequent year. Again, however, the researchers emphasized the absence of evidence for causality and the risk of bias from confounding.

Mirtazapine was the antidepressant associated with the highest incidence ratio of weight gain, but that drug was prescribed infrequently.

 

“From a clinical perspective, these observations reinforce the need for active body weight management to accompany widespread antidepressant treatment, although this might often be met with limited success,” the authors wrote. “The potential for weight gain may also be a consideration in the selection of individual antidepressant drugs.”

The research was funded by the National Health Service Foundation Trust and by King’s College London. Aside from one author’s employment with the U.K. Clinical Practice Research Datalink data source, the authors had no disclosures.

SOURCE: Gafoor R et al. BMJ. 2018;361:k1951. doi: 10.1136/bmj.k1951.

 

Taking antidepressants appears associated with weight gain in a recent study, though the researchers caution that the link might not be causal. Antidepressant use already was lowest in those with an initially normal BMI, and it increased with each category of greater BMI.

“Participants of normal weight showed an increased risk of transitioning to overweight or obesity, and overweight participants were more likely to become obese if they were treated with an antidepressant,” Rafael Gafoor, PhD, of King’s College London, and his associates wrote in BMJ.

“The risk of weight gain was substantially increased during the second and third years of treatment,” they reported. “The risk of weight gain remained increased during at least 6 years of follow-up.”

The researchers retrospectively analyzed EHRs from the U.K. Clinical Practice Research Datalink, representing about 7% of general practices in the United Kingdom, to compare the risk of weight gain among those who were and were not prescribed antidepressants. Of more than 2 million registered participants, a random sample of those with at least three measurements for body mass index (BMI), representing different weight classes, were included.

Out of 136,762 men and 157,957 women, 13% of the men and 22.4% of the women received prescriptions for antidepressants. The 10-year follow-up period included more than 1.8 million person-years. The proportion of people gaining at least 5% in BMI was 11.1% in those with antidepressants prescriptions, compared with 8.1% in those not prescribed antidepressants.

“Antidepressant use was greater in patients with comorbidity and coprescriptions, particularly with diagnoses of stroke and diabetes or coprescribing of antiepileptics or antipsychotics, than in those without,” the researchers wrote. “Antidepressant use was also associated with current smoking and higher deprivation category.”

The researchers adjusted the analysis to account for age, sex, initial BMI classification, smoking, prescriptions for antiepileptics or antipsychotics, year, region of residence, socioeconomic status, or having received advice on weight management or diet. They also accounted for diabetes, coronary heart disease, stroke, cancer, and depression diagnoses, and they eliminated the 280 days before a newborn delivery to account for pregnancy-related weight increases.

 

After adjustment for those potential confounders, people prescribed antidepressants were 21% more likely to experience substantial weight gain than those not prescribed them (adjusted rate ratio = 1.21; P less than .001). The researchers, cautioned, however, that residual confounding might have inflated the risk.

Those who had a normal weight when they began taking antidepressants had 29% greater risk of gaining enough weight to meet the criteria for overweight or obesity. Likewise, those already overweight when first prescribed antidepressants were 29% more likely to develop obesity.

For every 27 patients who took antidepressants for at least 1 year, 1 of them gained at least 5% in BMI during the subsequent year. Again, however, the researchers emphasized the absence of evidence for causality and the risk of bias from confounding.

Mirtazapine was the antidepressant associated with the highest incidence ratio of weight gain, but that drug was prescribed infrequently.

 

“From a clinical perspective, these observations reinforce the need for active body weight management to accompany widespread antidepressant treatment, although this might often be met with limited success,” the authors wrote. “The potential for weight gain may also be a consideration in the selection of individual antidepressant drugs.”

The research was funded by the National Health Service Foundation Trust and by King’s College London. Aside from one author’s employment with the U.K. Clinical Practice Research Datalink data source, the authors had no disclosures.

SOURCE: Gafoor R et al. BMJ. 2018;361:k1951. doi: 10.1136/bmj.k1951.

 

Taking antidepressants appears associated with weight gain in a recent study, though the researchers caution that the link might not be causal. Antidepressant use already was lowest in those with an initially normal BMI, and it increased with each category of greater BMI.

“Participants of normal weight showed an increased risk of transitioning to overweight or obesity, and overweight participants were more likely to become obese if they were treated with an antidepressant,” Rafael Gafoor, PhD, of King’s College London, and his associates wrote in BMJ.

“The risk of weight gain was substantially increased during the second and third years of treatment,” they reported. “The risk of weight gain remained increased during at least 6 years of follow-up.”

The researchers retrospectively analyzed EHRs from the U.K. Clinical Practice Research Datalink, representing about 7% of general practices in the United Kingdom, to compare the risk of weight gain among those who were and were not prescribed antidepressants. Of more than 2 million registered participants, a random sample of those with at least three measurements for body mass index (BMI), representing different weight classes, were included.

Out of 136,762 men and 157,957 women, 13% of the men and 22.4% of the women received prescriptions for antidepressants. The 10-year follow-up period included more than 1.8 million person-years. The proportion of people gaining at least 5% in BMI was 11.1% in those with antidepressants prescriptions, compared with 8.1% in those not prescribed antidepressants.

“Antidepressant use was greater in patients with comorbidity and coprescriptions, particularly with diagnoses of stroke and diabetes or coprescribing of antiepileptics or antipsychotics, than in those without,” the researchers wrote. “Antidepressant use was also associated with current smoking and higher deprivation category.”

The researchers adjusted the analysis to account for age, sex, initial BMI classification, smoking, prescriptions for antiepileptics or antipsychotics, year, region of residence, socioeconomic status, or having received advice on weight management or diet. They also accounted for diabetes, coronary heart disease, stroke, cancer, and depression diagnoses, and they eliminated the 280 days before a newborn delivery to account for pregnancy-related weight increases.

 

After adjustment for those potential confounders, people prescribed antidepressants were 21% more likely to experience substantial weight gain than those not prescribed them (adjusted rate ratio = 1.21; P less than .001). The researchers, cautioned, however, that residual confounding might have inflated the risk.

Those who had a normal weight when they began taking antidepressants had 29% greater risk of gaining enough weight to meet the criteria for overweight or obesity. Likewise, those already overweight when first prescribed antidepressants were 29% more likely to develop obesity.

For every 27 patients who took antidepressants for at least 1 year, 1 of them gained at least 5% in BMI during the subsequent year. Again, however, the researchers emphasized the absence of evidence for causality and the risk of bias from confounding.

Mirtazapine was the antidepressant associated with the highest incidence ratio of weight gain, but that drug was prescribed infrequently.

 

“From a clinical perspective, these observations reinforce the need for active body weight management to accompany widespread antidepressant treatment, although this might often be met with limited success,” the authors wrote. “The potential for weight gain may also be a consideration in the selection of individual antidepressant drugs.”

The research was funded by the National Health Service Foundation Trust and by King’s College London. Aside from one author’s employment with the U.K. Clinical Practice Research Datalink data source, the authors had no disclosures.

SOURCE: Gafoor R et al. BMJ. 2018;361:k1951. doi: 10.1136/bmj.k1951.