Prevalence of valvular-regurgitation associated with dexfenfluramine three to five months after discontinuation of treatment

Tratamento farmacológico da obesidade: passado, presente e futuro

O tratamento da obesidade deve ser baseado na percepção de que a obesidade é uma enfermidade crônica, neuroquímica e recidivante. Sendo assim, a combinação de eficácia, sustentabilidade de longo prazo e perfil de segurança de excelência devem nortear a utilização dos medicamentos disponíveis assim como das novas moléculas vindouras. No momento, a liraglutida parece ser a mais completa droga para a obesidade como doença crônica, mas certamente deverá ser superada pelos novos peptídeos de múltiplo agonismo e/ou pela combinação de várias medicações ainda não disponíveis em baixas dosagens para pacientes precisa e individualmente selecionados.

Anti-Obesity Therapy: from Rainbow Pills to Polyagonists

With their ever-growing prevalence, obesity and diabetes represent major health threats of our society. Based on estimations by the World Health Organization, approximately 300 million people will be obese in 2035. In 2015 alone there were more than 1.6 million fatalities attributable to hyperglycemia and diabetes. In addition, treatment of these diseases places an enormous burden on our health care system. As a result, the development of pharmacotherapies to tackle this life-threatening pandemic is of utmost importance. Since the beginning of the 19th century, a variety of drugs have been evaluated for their ability to decrease body weight and/or to improve deranged glycemic control. The list of evaluated drugs includes, among many others, sheep-derived thyroid extracts, mitochondrial uncouplers, amphetamines, serotonergics, lipase inhibitors, and a variety of hormones produced and secreted by the gastrointestinal tract or adipose tissue. Unfortunately, when used as a single hormone therapy, most of these drugs are underwhelming in their efficacy or safety, and placebo-subtracted weight loss attributed to such therapy is typically not more than 10%. In 2009, the generation of a single molecule with agonism at the receptors for glucagon and the glucagon-like peptide 1 broke new ground in obesity pharmacology. This molecule combined the beneficial anorectic and glycemic effects of glucagon-like peptide 1 with the thermogenic effect of glucagon into a single molecule with enhanced potency and sustained action. Several other unimolecular dual agonists have subsequently been developed, and, based on their preclinical success, these molecules illuminate the path to a new and more fruitful era in obesity pharmacology. In this review, we focus on the historical pharmacological approaches to treat obesity and glucose intolerance and describe how the knowledge obtained by these studies led to the discovery of unimolecular polypharmacology.

Aortic valvular regurgitation: prevalence and clinical characteristics in a predominantly obese adult population not taking anorexigens

BACKGROUND

We recently reported the prevalence of aortic regurgitation (AR) by Doppler echocardiography (echo) in obese subjects to be higher than in some previous reports.

OBJECTIVE

To describe the prevalence of AR in an obese population not taking anorexigens as a function of demographic characteristics, cardiovascular risk factors, and other potential predictors.

METHODS

In 539 adult subjects, cardiovascular status was evaluated by medical history, physical examination, and Doppler echocardiograms performed according to a standardized imaging protocol. Echocardiographic readers were blinded as to each subject's medical and medication histories. Associations of AR with demographic and comorbid factors were examined.

RESULTS

Subjects had a mean (+/- SD) body mass index (BMI) of 35 +/- 7 kg/m2, and were predominantly white (87.6%), females (74%), with a mean age of 47 +/- 12 years. AR by Food and Drug Administration criteria (> or =mild) was present in 4.1% of the subjects. Covariates significantly associated with AR were increasing age (P < 0.001), presence of a history of hypertension (P = 0.001), left ventricular (LV) internal dimensions (P < 0.005), and tricuspid and mitral regurgitation grade (P < 0.001).

CONCLUSIONS

Clinical and Doppler echo evaluation of a large, predominantly obese, adult population revealed that AR was more prevalent than in some previous reports and was highly correlated with increased age, presence of a history of hypertension, LV internal dimensions, tricuspid and mitral regurgitation.

Safety of drug therapies used for weight loss and treatment of obesity

Some of the medications used for weight loss in the management of obesity have been associated with unacceptable morbidity and mortality. Safety concerns have led to the withdrawal of aminorex, followed by the fenfluramines in 1997, and phenylpropanolamine (norephedrine) in 2000. Aminorex was associated with an increased prevalence of primary pulmonary hypertension (PPH), fenfluramines with an increased prevalence of PPH and valvulopathy, and phenylpropanolamine with an increased risk of haemorrhagic stroke. Several studies have investigated the safety of the fenfluramines, yet the benefit-risk profile has not been conclusively quantified. This is due to several deficiencies in the published studies, including a lack of data on the baseline prevalences of comorbid conditions in obese subjects, and potential confounders and biases in the study designs. Although several studies and systematic reviews support an increased risk of PPH and valvulopathy in patients who have taken fenfluramines, without knowledge of the background prevalence it is not possible to determine if the exposure preceded the outcome. The population at higher risk of these adverse effects includes those taking higher doses or with a longer duration of exposure to fenfluramines and those with pre-existing cardiac disease or a genetic predisposition. Patients exposed to fenfluramines continue to be monitored, with some follow-up studies indicating no overall worsening in valvulopathy over time. There are limited efficacy and safety data for amfepramone (diethylpropion) and phentermine and their approval for the management of obesity is limited to short-term use. Orlistat and sibutramine are the only currently approved medications for long-term management of obesity. Although the benefit-risk profiles of sibutramine and orlistat appear positive, sibutramine continues to be monitored because of long-term safety concerns. The safety and efficacy of currently approved drug therapies have not been evaluated in children and elderly patient populations and there is limited information in adolescents, whilst the long-term safety of current and potential new drug therapies in adults will require several years of postmarketing surveillance to fully elucidate their adverse effect profiles.

The patient with a heart murmur: evaluation, assessment and dental considerations

BACKGROUND

Heart murmurs, a common finding in dental patients, are of major concern to dental professionals because certain dental procedures occasionally can induce severe cardiovascular complications. Murmurs may indicate existing heart disease that is a risk factor for infective endocarditis following a dental procedure, as well as more severe heart conditions such as congenital heart disease, atrial fibrillation or congestive heart failure.

TYPES OF STUDIES REVIEWED

This review article is based on data published in peer-reviewed journals, including practice guidelines published by major dental and medical professional organizations.

RESULTS

Echocardiography is the primary means of evaluating heart murmurs, and all dental professionals should become familiar with major aspects of an echocardiogram. Understanding the medical evaluation and assessment of a heart murmur fosters better communication with other health care professionals and results in improved patient care.

CLINICAL IMPLICATIONS

Beyond the need to administer antibiotic prophylaxis, the dentist also needs to address the underlying causes of a patient's heart murmur. By providing dental care to such patients, oral health care providers become part of the patient's overall health care team.

Effect of fenfluramine-derivative diet pills on cardiac valves: a meta-analysis of observational studies

BACKGROUND

Fenfluramine-derivative diet pills were withdrawn from the market in 1997 because of an association with valvular regurgitation, but subsequent estimates of the prevalence of this condition have varied widely. We systematically reviewed evidence regarding the prevalence of valvular disease after fenfluramine exposure.

METHODS

We searched multiple databases with multiple search terms. Conference proceedings from 1997 onward were searched by index. Authors of eligible studies were contacted to identify unpublished works. Selection criteria were liberally determined. Ten of the identified 11 articles met these criteria. Reviewers assessed the studies' methodologic quality by use of a standard form to evaluate selection, attrition, performance, and detection bias. The studies were analyzed in 2 groups on the basis of length of exposure (<90 days or >90 days). The Mantel-Haenszel method was used to summarize data. Quantitative and qualitative tests for heterogeneity were performed. Tests for publication bias were also done.

RESULTS

Tests for heterogeneity were nonsignificant after removing 1 outlier trial. The pooled prevalence of valvular regurgitation meeting Food and Drug Administration criteria (at least mild aortic regurgitation or at least moderate mitral regurgitation) among patients treated for >90 days was 12.0% compared with 5.9% for the unexposed group (prevalence odds ratio 2.2, 95% CI 1.7-2.7). The combined analyses also identified a small but statistically significant increase in mitral regurgitation not previously identified by individual studies (exposed 3.5%, unexposed 1.8%, prevalence odds ratio 1.6, 95% CI 1.05-2.3). Among patients exposed for <90 days, a trend toward more regurgitation was not statistically significant by either combined Food and Drug Administration criteria (exposed 6.8%, unexposed 5.8%, prevalence odds ratio 1.4, 95% CI 0.8-2.4) or by individual valve.

CONCLUSIONS

These data indicate that fenfluramine-associated valvular regurgitation is less common than initially reported, but still present in 1 of 8 patients treated for >90 days.

Quantitative analysis of human heart valves: does anorexigen exposure produce a distinctive morphological lesion?

The need for more detail regarding the clinical and morphological features of human heart valves has become evident due to recent controversy regarding anorexigen-associated valvular dysfunction. In the present study, we used quantitative digital image analysis of geometric and compositional features to compare the histopathology of cardiac valves excised from patients treated with anorexigens as compared to normal, floppy, rheumatic and carcinoid valves. Anorexigen-exposed valves had the greatest number of onlays/valve (P<.0001), while rheumatic valves showed the greatest average onlay size and thickness of the comparison groups studied (P=.01). The valve onlays from anorexigen-exposed, carcinoid and floppy valves contained a greater percentage of glycosaminoglycans (GAGs) as compared to normal and rheumatic valves (P=.01). The anorexigen-exposed valve propers contained more GAGs than any other comparison group (P=.02). Vessels were prominent in both onlay and valve proper regions of carcinoid valves, in the anorexigen-exposed valve onlays and in rheumatic valve propers. Thus, the number of onlays, their size, the degree of GAG deposition, and the presence and location of vessels and leukocytes were important features distinguishing anorexigen-exposed valves from normal valves. Discriminant analyses, based on geometry, color composition or color composition, and vessel and leukocyte counts combined, were able to separate the valves into distinguishable groups. Our findings demonstrate that specific microscopic features can be used to separate anorexigen-associated heart valve lesions from normal valves and valve lesions associated with other pathologies, and suggest that a distinctive pathological process may exist in many anorexigen-exposed valves.

Appetite suppressants and valvular heart disease in a population-based sample: the HyperGEN study

PURPOSE

Previous studies of the association between the use of appetite suppressants and valvular heart disease have not accounted for the effects of valvular structure and aortic root diameter, which are associated with obesity. We assessed whether the use of the appetite suppressants fenfluramine/dexfenfluramine, either alone or with phentermine, was associated with aortic regurgitation while adjusting for these variables.

SUBJECTS AND METHODS

The sample included 2524 adult participants in the population-based Hypertension Genetic Epidemiology Network study. Information regarding current drug use was assessed during a clinical examination. Medication use was continued at the time of echocardiographic study. Expert readers blinded to current therapy read echocardiograms centrally at Cornell Medical Center. Analyses of the associations between use of fenfluramine/dexfenfluramine (alone or with phentermine) and aortic regurgitation adjusted for potential confounders, including aortic root dilatation and valve fibrocalcification.

RESULTS

Nineteen participants, all of whom had hypertension, were being treated with fenfluramine or dexfenfluramine (5 on these agents alone, 14 also with phentermine). Aortic regurgitation was present in 32% (n = 6) of those taking fenfluramine or dexfenfluramine versus 6% (162/2505) of remaining subjects (P = 0.001). In multivariate-adjusted analyses, treatment with fenfluramine or dexfenfluramine was associated with aortic regurgitation (odds ratio [OR] = 4.9; 95% confidence interval [CI]: 1.7 to 14) and aortic fibrocalcification (OR = 5.2; 95% CI: 1.9 to 15).

CONCLUSION

In a population-based sample, use of fenfluramine or dexfenfluramine, alone or in combination with phentermine, was associated with aortic regurgitation independent of aortic dilatation or fibrocalcification.

Reversal of Phen-Fen associated valvular regurgitation documented by serial echocardiography

We report a case of anorexigen-associated moderate to severe aortic and mitral regurgitation in which the regression of lesions was marked and well documented over more than 2 years. The stability of our patient, as well as the degree of regression of regurgitation documented in our patient, and others, suggests it is prudent both to observe such patients and to avoid operation until such observation has been carried out.

Low risk of significant echocardiographic valvulopathy in patients treated with anorectic drugs

BACKGROUND

Phentermine--fenfluramine and dexfenfluramine use for weight loss has been previously associated with increased prevalence of valvular heart disease. This association was initially based on small numbers of patients, limited data on dose and duration of drug therapy, and no correlation with matched controls.

METHODS

Our investigation involved 343 obese subjects enrolled in a prospective, strict weight loss, research protocol from September 1994 to September 1997. All subjects underwent transthoracic echocardiography for significant valvular lesions within a mean of 121 days from the manufacturer's announcement of the voluntary withdrawal of fenfluramine and dexfenfluramine from the market. All echocardiograms were interpreted by 2 independent readers.

RESULTS

The study population included 281 females and 62 males with a mean age of 46.7+/-9.1 years and mean initial body mass index of 40.1+/-8.1 kg/m(2). Using the Food and Drug Administration's criteria, only 21 subjects (6.1%) had significant valvular lesions. Aortic regurgitation was detected in 18 subjects, mitral regurgitation in 3 subjects, and both aortic and mitral regurgitation in 1 subject; no one had severe regurgitation. Significant valvular disease did not correlate with age, gender, initial/ending body mass index, the drug dose, duration of drug therapy, or serotonin reuptake inhibitors.

CONCLUSIONS

Anorexigen therapy is associated with a low prevalence of significant valvular regurgitation. Late valvular abnormalities from drug treatment await long term prospective studies.

Specificity of Doppler echocardiography for the assessment of changes in valvular regurgitation: comparison of side-by-side versus serial interpretation

OBJECTIVES

We sought to determine the specificity of two different methods for assessing change in aortic (AR), mitral (MR) and tricuspid (TR) valvular regurgitation.

BACKGROUND

Echocardiographic imaging with Doppler is the standard noninvasive diagnostic tool for assessing valvular structure and function. Change can be assessed using either independent evaluations (serial) or using a side-by-side comparison.

METHODS

Subjects were from the placebo arm of a randomized, double-blind, clinical trial. Three echocardiograms over 10 months were performed. An initial and three-month echocardiogram were read as independent groups, blinded to all parameters except sequence. The initial and 10-month echocardiograms were read side-by-side, blinded to all parameters including sequence.

RESULTS

Two hundred nineteen predominantly healthy, obese, white, middle-aged women had initial and three-month echocardiograms (acquisition interval 105 +/- 28 days) evaluated by the serial method (mean 167 +/- 61 days between interpretations). The same subjects had the initial and 10-month studies (acquisition interval 303 +/- 27 days) compared side-by-side. The specificity of the serial versus side-by-side method for determining change in MR grade was 55.8% versus 93.2% (p < 0.001); TR: 63.8% versus 97.6% (p < 0.001) and AR: 93.7% versus 97.6 (p = 0.08). Notably, most of the change occurred in a range (none versus physiologic/mild) that has limited clinical significance. Furthermore, the percentage of echocardiograms interpreted as nonevaluable was lower with the side-by-side method for MR (5.0% vs. 16.0%, p = 0.06), TR (4.6% vs. 15.5%, p < 0.001) and AR (4.1% vs. 12.3%, p = 0.002).

CONCLUSIONS

The side-by-side method of assessing change in valvular regurgitation appears to be the more reliable method with a higher specificity and minimal data loss.

Prevalence and diagnostic value of precordial murmurs for valvular regurgitation in obese patients treated with dexfenfluramine

Echocardiography is recommended for the detection of valvular regurgitation in asymptomatic users of anorexigens with a heart murmur. To determine the prevalence and diagnostic value of heart murmurs for valvular regurgitation, 223 patients receiving dexfenfluramine therapy for 6.9 months and 189 matched controls underwent history and cardiac auscultation by experienced noncardiologists unaware of echocardiography. Color Doppler echocardiograms were interpreted by 3 observers unaware of patients' clinical data. The frequency of at least mild regurgitation of any valve and abnormal regurgitation (moderate mitral or tricuspid or mild aortic regurgitation) were determined. Heart murmurs heard in 31 dexfenfluramine users (14%) and in 20 controls (11%) were all systolic and of grade I to II/VI intensity. Mild or worse regurgitation of any valve showed a trend in patients (18% vs 11.6% in controls, odds ratio [OR] 1.66, confidence interval [CI] 0.95 to 2.9, p = 0.08), but abnormal regurgitation (includes Food and Drug Administration grade regurgitation) was more common in patients (9% vs 3% in controls, OR 3.0, CI 1.18 to 7.65, p = 0.02). In dexfenfluramine users, heart murmurs were associated with at least mild or abnormal regurgitation (OR 3.1 and 3.05, 95% CI 1.34 to 7.13 and 1.1 to 8.67; p = 0.008 and 0.036, respectively), had a specificity of 89% and 88%, negative predictive value of 85% and 93%, but sensitivity of 37% and 30%, and positive predictive value of 35% and 19%, respectively. Most valves missed by cardiac auscultation had normal morphology and mild regurgitation. Finally, heart murmurs had better diagnostic value for either type of valvular regurgitation than heart murmurs and clinical variables or clinical variables alone. In summary, in dexfenfluramine users the prevalence of heart murmurs was low and their absence predicted absence of mild or worse regurgitation of any valve or abnormal valvular regurgitation. Therefore, cardiac auscultation should be the screening method of choice for detecting valvular regurgitation in users of anorexigens.

Diet drug-related cardiac valve disease: the Mayo Clinic echocardiographic laboratory experience

OBJECTIVE

To describe the prevalence of diet drug-related valvular disease among our referral population and the association of valvular disease with duration of exposure to fenfluramine and phentermine in combination and to dexfenfluramine alone.

PATIENTS AND METHODS

In this retrospective review of clinical and echocardiographic data, charts of patients referred for treatment of toxic effects of diet drugs were reviewed, and telephone interviews were conducted.

RESULTS

Between June and December 1997, 191 patients (164 women, 27 men; mean age, 47 years) were referred for possible diet drug-related valvular disease. Twenty-eight (28%) of the 99 asymptomatic patients and 40 (43%) of the 92 symptomatic patients had abnormal echocardiographic findings. Valvular lesions among the 68 patients with abnormal echocardiographic findings included mild (or greater) aortic regurgitation in 55 patients (81%), moderate (or greater) mitral regurgitation in 12 (18%), and moderate (or greater) tricuspid regurgitation in 7 (10%). The Food and Drug Administration case definition of diet drug-related valvulopathy was noted in 31 % of this referral population. Of patients with valvulopathy, mean duration of therapy with fenfluramine and phentermine in combination and dexfenfluramine alone was 9 months and 5 months, respectively. Duration of therapy was not associated with presence or absence of disease. Five patients had surgical intervention for severe valvulopathy: 3 had mitral valve repair, 1 had mitral valve replacement, and 1 had aortic valve replacement. Pulmonary hypertension (>40 mm Hg) was found in 24 patients (13%), and 17 (71 %) had pulmonary hypertension in association with valvulopathy.

CONCLUSION

This study demonstrated a 31% (60/191) prevalence of valvulopathy in patients with a history of diet drug exposure who were referred for echocardiographic evaluation. The most common finding was mild aortic regurgitation. Twenty-eight percent of asymptomatic patients had abnormal echocardiographic findings. This study emphasizes the spectrum of diet drug-related cardiac disease and the potential for valvulopathy in asymptomatic patients.