Answers to Self-Assessment Questions - ACCP

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there is insufficient evidence to support efficacy and drug interactions are a concern for L.B.) is the correct response, and Answer A (ginkgo is free of drug interactions with L.B.’s drugs) is incorrect. 1. Carlson JJ, Farquhar JW, DiNucci E, Ausserer L, Zehnder J, Miller M, et al. Safety and efficacy of a Ginkgo biloba– containing dietary supplement on cognitive function, quality of life, and platelet function in healthy, cognitively intact older adults. J Am Diet Assoc 2007;107:422–32. 2. Schneider LS, DeKosky ST, Farlow MR, Tariot PN, Hoerr R, Kieser M. A randomized, double-blind, placebo-controlled trial of two doses of Ginkgo biloba extract in dementia of the Alzheimer’s type. Curr Alzheimer Res 2005;2:541–51. 72. Answer: C Most published studies examining the effects of ginkgo in tinnitus lack sufficient methodology to interpret their results accurately and there is insufficient evidence that ginkgo is effective for tinnitus. Therefore, Answer A (several strong studies indicate effectiveness, but adverse effects preclude it use) and Answer D (it is well tolerated, and evidence suggests it is effective) are both incorrect. Although the first half of Answer B pertaining to efficacy is correct, ginkgo is generally well tolerated; therefore, Answer B (evidence fails to support efficacy, and adverse effects preclude its use) is incorrect. By the time a patient presents with distressing tinnitus, there is a significant psychological component present as well, which creates a strong placebo effect. This placebo effect makes it difficult to interpret results from clinical trials; therefore, Answer C (because of the strong placebo effect noted in tinnitus management, trials using ginkgo for tinnitus are difficult to interpret) is correct. 1. DerMarderrosian A, ed. The Review of Natural Products. St. Louis, MO: Elsevier Inc., 2007. 2. Hilton M, Stuart E. Ginkgo biloba for tinnitus. Cochrane Database Syst Rev 2004;2:CD003852. 73. Answer: A B.L. is a 66-year-old moderately obese woman with chronic, bilateral knee pain caused by moderately severe osteoarthritis. She takes acetaminophen for the pain but is interested in learning more about glucosamine. The overall response rate in the Glucosamine/chondroitin Arthritis Intervention Trial (GAIT) in participants receiving glucosamine, chondroitin, and the combined treatment was similar to that achieved with placebo. However, in a subgroup analysis of patients with moderate to severe pain at baseline, a significantly higher response rate was reported with combined therapy than with placebo. Based on this information, Answer A (patients with moderate to severe knee pain are more likely to benefit from glucosamine combined with chondroitin than patients with milder pain) is correct. The GAIT study used glucosamine hydrochloride and chondroitin sulfate, and the study was conducted under an Investigational New Drug Application filed with the FDA; therefore, the products used in this study were subject to more stringent regulations compared with other over-the-counter products. The Glucosamine Unum In Die Efficacy (GUIDE) trial used a prescription glucosamine sulfate product manufactured by the European pharmaceutical company, Rottapharm, and this product is not currently available in the United States. Because of a lack of standardization of Gastroenterology and Nutrition Answers 52 glucosamine products in the United States, together with highly variable amounts of glucosamine contained in these products, extrapolation of the results from either GAIT or GUIDE cannot be recommended. Therefore, Answer B (products used in GAIT and GUIDE are similar to those available in the United States) is incorrect. The Western Ontario and McMaster University (WOMAC) and Lequesne indices were used to measure the primary outcomes in this study. The importance of addressing the implications of using differing measures of primary outcomes in clinical trials when evaluating response rates is understood. The WOMAC index appears to be more sensitive than the Lequesne index. Therefore, Answer C (they demonstrate comparable validity, reliability, and responsiveness to glucosamine) is incorrect. Although most of the published trials examining the use of glucosamine in patients with osteoarthritis indicate it is generally well tolerated with a safety profile significantly superior to nonsteroidal antiinflammatory drugs (NSAIDs), most of these trials have been short, lasting 6 months or less. Long-term safety information beyond 6 months cannot be ascertained at this time, making Answer D (the long-term safety profile is superior to NSAIDs) incorrect. 1. Gentell-Bonnassies S, Le Claire P, Mezieres M, Ayral X, Dougados M. Comparison of the responsiveness of symptomatic outcome measures in knee osteoarthritis. Arthritis Care Res 2000;13:280–5. 2. Clegg DO, Reda DJ, Harris CL, Klein MA, O’Dell JR, Hooper MM, et al. Glucosamine, chondroitin sulfate, and the two in combination for painful knee osteoarthritis. N Engl J Med 2006;354:795–808. 3. Herrero-Beaumont G, Ivorra JA, Del Carmen Trabado M, Blanco FJ, Benito P, Martin-Mola E, et al. Glucosamine sulfate in the treatment of knee osteoarthritis symptoms: a randomized, double-blind, placebo-controlled study using acetaminophen as a side comparator. Arthritis Rheum 2007;56:555–67. 74. Answer: B The Glucosamine/chondroitin Arthritis Intervention Trial used a robust study design (a randomized, doubleblind, placebo- and celecoxib-controlled multicenter design); however, the study design cannot correct for a higher-than-expected placebo response and lower-thanexpected celecoxib response. In addition, inclusion of patients with mild symptoms may have resulted in less sensitivity to the outcome measures. Therefore, Answer A (they are of minimal concern in this trial because of the robustness of the study design) is incorrect. The high placebo response rate, together with the lower-than-expected celecoxib response rate, may limit the ability to detect true treatment benefits, thus increasing the risk of mistakenly failing to reject the null hypothesis when the alternative hypothesis is true (a type II error); therefore, Answer B (may mask true response rates to glucosamine, increasing the risk of a type II error) is correct. Type I errors (Answer C) occur when a true null hypothesis is rejected; therefore, Answer C is incorrect. Although the authors did perform a power analysis, readers should realize that statistical power depends on the statistically significant criterion (a = 0.017 for comparisons of glucosamine, chondroitin, and combined-treatment group with placebo, with an overall a = 0.05), the effect size, and the sensitivity of the data. The Pharmacotherapy Self-Assessment Program, 6th Edition
claimed effect size in GAIT was an absolute increase of 15% in the response rate compared with placebo, assuming a 35% response rate in the placebo group. The much larger placebo response reported in GAIT would make it more difficult to detect the effect size. Therefore, Answer D (there is minimal concern in this trial because of the successful use of a power analysis) is incorrect. 1. Towheed TE, Maxwell L, Anastassiades TP, Shea B, Houpt J. Robinson V, et al. Glucosamine therapy for treating osteoarthritis. Cochrane Database Syst Rev 2005;2:CD002946. 2. Guller U, DeLong E. Interpreting statistics in medical literature: a vade mecum for surgeons. J Am Coll Surg 2004;198:441–58. 75. Answer: C T.G. is a 49-year-old man with hypercholesterolemia being treated with atorvastatin. He is interested in obtaining information regarding the use of policosanol. Although early studies of Cuban sugar cane policosanol showed promising results in lipid-lowering effects, recent studies have not substantiated these results. In a double-blind, placebocontrolled trial, adding policosanol to atorvastatin (Answer A) showed no better lipid-lowering effect than atorvastatin alone. Other recent studies of policosanol have demonstrated that results with its use are no better than placebo in reducing low-density lipoprotein cholesterol (LDL-C). Therefore, Answer B (replacement of atorvastatin with policosanol would result in similar lowering of LDL-C) is incorrect. The advice that policosanol should not be expected to lower LDL-C is based on its lack of efficacy (Answer C), making Answer C the correct response. Policosanol is relatively free of adverse events such as elevated liver function tests or elevated creatine phosphokinase, making Answer D (it has the potential to elevate creatine phosphokinase concentrations) incorrect. 1. Cubeddu LX, Cubeddu RJ, Heimowitz T, Restrepo B, Lamas GA, Weinberg GB. Comparative lipid-lowering effects of policosanol and atorvastatin: a randomized, parallel, double-blind, placebo-controlled trial. Am Heart J 2006;152:982.e1–5. 2. Berthold HK, Unverdorben S, Degenhardt R, Bulitta M, Gouni-Berhold I. Effect of policosanol on lipid values among patients with hypercholesterolemia or combined hyperlipidemia: a randomized controlled trial. JAMA 2006;295:2262–9. 76. Answer: D C.D. is a 32-year-old moderately obese woman who is seeking advice on the use of Saint John’s wort for postpartum depression. Although recent literature does not indicate a significant interaction between hypericum and oral contraceptives, the potential for such an interaction cannot be excluded; therefore, Answer A (current evidence fails to substantiate significant drug interactions between Saint John’s wort and oral contraceptives) is incorrect. Lovastatin undergoes similar metabolism compared with simvastatin, with CYP P450 3A4 playing a major part in its metabolism, as well as being a potential substrate for P-glycoprotein. Therefore, a significant interaction with hypericum is likely, which may result in significantly reduced bioavailability of lovastatin. Therefore, Answer B (significant interactions with Saint John’s wort and lovastatin are unlikely) is incorrect. Because C.D. is described to be suffering from major depression (i.e., postpartum depression), Answer C (recent evidence suggests benefit of hypericum extracts in patients with mild to moderate depression and is therefore a viable option for C.D.) is incorrect. Although older studies have suggested a benefit of hypericum compared with placebo for the treatment of major depression, more recent, methodologically robust studies fail to support these results. Although the consensus continues to indicate its efficacy in the treatment of symptoms associated with mild to moderate depression, more studies are needed to further ascertain its role in the treatment of major depression. Therefore, Answer D (recent data suggest Saint John’s wort is no more efficacious than placebo for the treatment of major depression such as C.D. is experiencing) is correct because C.D. appears to meet criteria for major depression. 1. Madabushi R, Frank B, Drewelow B, Derendorf H, Butterweck V. Hyperforin in St. John’s wort drug interactions. Eur J Clin Pharmacol 2006;62:225–33. 2. Whitten DL, Myers P, Hawrelak A, Wolhmuth H. The effect of St. John’s wort extracts on CYP3A: a systematic review of prospective clinical trials. Br J Clin Pharmacol 2006;62:512– 26. 3. Hypericum Depression Trial Study Group. Effect of Hypericum perforatum (St. John’s wort) in major depressive disorder: a randomized controlled trial. JAMA 2002;287:1807–14. 4. Fava M, Alpert J, Nierenberg AA, Mischoulon D, Otto MW, Zajecka J, et al. A double-blind, randomized trial of St. John’s wort, fluoxetine, and placebo in major depressive disorder. J Clin Psychopharmacol 2005;25:441–7. 77. Answer: D Equol is an isoflavone formed by bacterial intestinal metabolism of the soy isoflavone daidzein. Equol has greater affinity for the estrogen receptor than daidzein, and activity at the estrogen receptor is believed to be important for the activity of soy in cardioprevention and for relief of menopausal symptoms. Only about one-third of non-Asian people can form equol from daidzein, so it is plausible that these populations may derive less benefit from soy isoflavones compared with Asian populations in which a higher percentage of the constituency are equol formers. Thus, Answer A (most Americans are equol formers) is incorrect. Although soy food supplementation has resulted in blood pressure lowering in hypertensive patients in some studies, this result has not been consistent across studies. Thus Answer B (blood pressure reduction is expected with soy isoflavones) is incorrect. The lipid-lowering effects of soy have been found to be more modest in recent studies compared with older studies. These recent effects of a 3% to 5% reduction in LDL-C are lower than those typically seen with statin agents, making Answer C (the effects are similar) an incorrect answer. The most compelling reason for incorporating more soy into the animal protein–rich American diet is that this will tend to decrease dietary saturated fat and cholesterol (Answer D); thus Answer D is the correct answer. 1. Reynolds K, Chin A, Lees KA, Nguyen A, Bujnowski D, He J. A meta-analysis of the effect of soy protein supplementation on serum lipids. Am J Cardiol 2006;98:633–40. 2. Nettleton JA, Greany KA, Thomas W, Wangen KE, Adlercreutz H, Kurzer MS. The effect of soy consumption on the urinary Pharmacotherapy Self-Assessment Program, 6th Edition 53 Gastroenterology and Nutrition Answers
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