You learn that a 54 Y/O man with NIDDM (on oral hypoglycaemics) whose myocardial infarction you treated 6 months ago has died suddenly at home. Wondering whether you could have done more for him, you review his notes and confirm that he was, in fact, a low risk inferior MI with no complications whose blood sugar was elevated on admission (13 mmol/L) but settled down within three days.
In view of the success of "tight control" of IDDM in preventing or postponing retinopathy and neuropathy, you wonder if a more aggressive treatment of his NIDDM might have postponed his untimely death. On the other hand, you well recall how one of your Profs back in medical school insisted that insulin was atherogenic and how you should back off insulin doses when diabetics developed angina pectoris.
So you form the clinical question:
"Among patients with NIDDM who are having MI's, does tight control of their blood sugar reduce their risk of dying?"
You ask the librarian at your local Post-Graduate Centre to help you, and she finds (The terms she used were: diabetes mellitus AND myocardial infarction AND publication type=randomized controlled trial) the attached article: Malmberg K et al: Randomized trial of insulin-glucose infusion followed by subcutaneous insulin treatment in diabetic patients with acute myocardial infarction (DIGAMI Study). J Am Coll Cardiol 1995;26:57-65.
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A 70 year old man sustained a myocardial infarction three years ago. He experienced some heart failure after the infarction, but has done well while taking captopril, furosemide, aspirin, and a beta blocker. He was free of symptoms or signs of heart failure, or angina, until approximately one month ago. He reports that at that time he began to feel increasingly fatigued. He denies shortness of breath, othopnea, paroxysmal nocturnal dyspnoea, ankle swelling, weight gain, or chest pain. He just feels that he doesn't have the energy he did, and needs to take frequent rests and a nap in the afternoon. Physical examination reveals no sign of heart failure, and no other abnormalities. Initial laboratory examination shows a haemoglobin of 10.0 g/dl, with notable findings on the blood film, and a mean cell volume of 82. Serum ferritin is ordered.
While waiting for it to return, you ask yourself whether serum ferritin is really the best way to determine iron deficiency in such a patient. You find the enclosed article: Guyatt GH, Patterson C, Ali M, et al: Diagnosis of iron-deficiency anaemia in the elderly. AM J Med 1990;88:205-209.
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You are an SHO on a new assignment in the medical out-patient department. Your first patient for the afternoon is a 69 year old white woman, a retired high school teacher, who you are seeing back today to review her test results. A month ago she presented with symptoms and signs of congestive heart failure. She has had long-standing essential hypertension, but had been otherwise healthy until now.
A 12-lead ECG shows left ventricular hypertrophy. A transthoracic echocardiogram shows left ventricular dilatation and hypertrophy. Both diastolic and systolic function are impaired; the estimated ejection fraction is 35%.
You review with the patient the test results, her medication use and how she's done since you last saw her. Then she asks you, "Heart failure sounds serious - is it? What do I have to look forward to?" You excuse yourself and find your Consultant.
Together, you and your Consultant form the clinical question: In a patient with heart failure and poor left-ventricular function, what is the average survival time? You perform a search on the library's MedLine system available on the clinic's computer. Entering "*heart failure, congestive" yields 3865 articles in the current MedLine file. Your Consultant points out that cohort studies should provide the most valid and useful information about prognosis. Entering "cohort studies" yields 6156 articles, and crossing the two sets yields 8 articles. As you review them on-screen, the first one appears directly relevant <Ho, et al>. After an electronic mail request to the library the full text of the article arrives from the library by fax in a few minutes: Ho KK, Anderson KM, Kannel WB, Grossman W, Levy D. Survival after the onset of congestive heart failure in Framingham Heart Study subjects. Circulation 1993 (Jul); 88(1): 107-115.
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A 45 year-old car mechanic who has been a patient of yours for over a decade has asked for a special appointment, requesting an hour of your time. Intrigued, you have consented. She informs you that, along with a number of other citizens, she has become increasingly concerned about levels of air pollution in your city. They are particularly concerned about health effects and over the last six months have examined the literature concerning the health impact of poor air quality. As they read what is available, their concern increased, and they were surprised at how ignorant they were of the evidence that their health was being adversely effected by air pollution. They were ultimately spurred to action by a recently published article suggesting that high levels of air pollution increase overall mortality in general populations. When the group compared the air pollution in your town to that of the cities monitored in the study, they found that your town had levels comparable to St. Louis, the city with the second highest mortality in the published report.
The group has adopted a formal structure, and a name: CAAP (Citizens Against Air Pollution). They are currently planning a public awareness campaign, and a lobbying campaign directed at municipal politicians. They believe that since they are going to focus their efforts on health effects of air pollution, their credibility hinges on the support and participation of as many local physicians as possible. Your patient is asking you to become a member of the group, have your name on their letterhead, and attend some of their educational and lobbying meetings.
You remain intrigued, but before deciding how to proceed you feel that you need to be aware of the evidence that has stimulated your patients' concern. You don't have much reading time, so you ask your patient to choose the paper she found most compelling. She does so, hands you the attached paper (Dockery DW, Pope CA, Xu X, et. al. An association between air pollution and mortality in six U.S. cities. N Engl J Med 1993;329:1753-9.), and arranges to come back and speak with you once again in a week's time.
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A 58-year-old man is referred to you for your advice on whether he should receive treatment for his cholesterol. His GP did a blood test and found a cholesterol level of 8.2. You enquire about his previous medical history, which includes:
1. Appendectomy 24 years ago.
2. Migraine for last 5 years.
There is no family record of IHD, CVA or diabetes. On further enquiry you learn that he is a non-smoker and consumes 4 units of alcohol per day. He is very health conscious and performs regular exercise for about 30 to 45 minutes per day on his exercise bicycle at home. His weight is 72 kg and height is 1.82 m.
You agree to examine this question in further detail and arrange to see him one week later.
You find the article: Davey Smith, G, Song F, Sheldon, T A. Cholesterol lowering and mortality: the importance of considering initial level of risk. BMJ 1993; 306: 1367-1373.
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A 72-year old woman is referred to you by her GP. She describes two distressing episodes that have happened in the last month. On one occasion her right arm became weak, clumsy, and numb. Initially, she had difficulty using the arm, and then difficulty even moving the arm. The entire episode lasted half and hour, and the arm function then returned to normal. On the second occasion, about two weeks later, her arm became only slightly weak, but she found it very difficult to speak. In particular, she couldn't think of words, or construct a coherent sentence. The second episode lasted ten minutes. She was completely lucid during each of these episodes.
She has a history of mild hypertension controlled with hydrochlorthiazide and no other medical problems. She has a family history of coronary artery disease, but no history of stroke in the family. Her cholesterol has been measured and is normal.
On physical examination you find that she is in sinus rhythm, has a II out of VI systolic ejection murmur, a left carotid bruit, and a left femoral bruit. Physical examination is otherwise normal. You prescribe enteric-coated aspirin in a dose of 325 mg. per day, and order an electrocardiogram and an echocardiogram which are both normal. A carotid Doppler shows less than 50% stenosis on both the left and the right.
The patient returns after the investigations and reports that she has not had another episode since beginning aspirin. However, she says that she has talked about the problem with her friends, and one woman with a very similar story is taking a drug called ticlopidine. This woman's doctor claims that ticlopidine is more effective than aspirin in the prevention of strokes, and wonders why you are giving her an inferior drug. You reply that you are aware that practice guidelines issued by a reputable organisation recommend the use of aspirin for people like the patient. The patient is puzzled by the discrepancy between what she has heard and what the guideline says, and asks if you can clarify further. You tell her you will review the guideline, and get back to her.
You find the guideline: American College of Physicians. Guidelines for medical treatment for stroke prevention. Ann Intern Med 1994;121:54-55.
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You have been appointed to sit on your hospital's Drug Utilisation Review Committee. As one of its first tasks, the Committee has decided to review the relative costs of the drugs listed on the hospital's formulary, particularly those that are prescribed routinely. During this process, metoprolol was identified by a pharmacy resident as having shown a substantial increase in use over the last few years, consuming an increasing share of the pharmacy budget. In the discussion that followed, it was learned that the current clinical policy of the cardiology service is to treat all appropriate myocardial infarction patients with metoprolol for three years. Two of the Committee members (a paediatrician and a family physician) question whether metoprolol is effective. You state that, to the best of your knowledge, it is regarded as effective in preventing the recurrence of M.I. The discussion then turns to cost, with one member claiming that the cost of the drug is more than offset by the economic consequences of reduced morbidity and mortality. Others argue that, given the effectiveness of metoprolol, it would be unethical to contemplate restricting its use based on cost considerations anyway.
Because you have a working knowledge of the use of the medication (and are the newest member of the Committee), the chairman of the Committee has asked you to review the evidence on the efficiency (i.e., cost-effectiveness) of metoprolol and report back. You do a CD-ROM MEDLINE search (using the terms "metoprolol" and "cost-effectiveness" and "myocardial infarction") and come up with just one article (attached): Olsson G, Levin L, Rehnqvist N. Economic Consequences of Postinfarction Prophylaxis with - blockers: Cost Effectiveness of Metoprolol. Brit Med J 1987;294:339-342.
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