Journal of the New Zealand Medical Association, 24-April-2009, Vol 122 No 1293
Two trial reports and an editorial on this controversial topic feature in a recent New England Journal. The first from the US National Cancer Institute reports on a randomised trial involving nearly 77,000 men over the age of 54 years. Half of them were offered annual PSA (prostate specific antigen) testing for 6 years and digital rectal examination for 4 years and the other half had routine care. And after 7 to 10 years follow-up, the rate of death from prostate cancer was very low and did not differ significantly between the two study groups.
The other trial was conducted in the Netherlands—182,000 men between 55 and 69 years of age. Half had annual PSA testing and the other half routine care. The authors conclude that PSA-based screening reduced the rate of death from prostate cancer by 20% but was associated with a high risk of overdiagnosis. However, they point out that this means that 1430 men would need to be screened and 48 additional cases of prostate cancer would need to be treated to prevent one death from prostate cancer.
And to quote the editorial commentary—“Serial PSA screening has at best a modest effect on prostate cancer mortality during the first decade of follow-up. This benefit comes at the cost of substantial overdiagnosis and overtreatment. It is important to remember that the key question is not whether PSA screening is effective but whether it does more good than harm.”
N Eng J Med 2009;360:1310–9, 1320–8 & 1351–4.
This report is from the Canadian Agency for Drugs and Technologies in Health, and the authors have set out to validate the claims that insulin analogues such as insulin lispro and insulin glargine are superior to the conventional rapid and long-acting insulins. Their meta-analyses included 68 randomised controlled trials in the analysis of rapid-acting insulin analogues and 49 in the analysis of long-acting insulin analogues.
They concluded that rapid and long-acting insulin analogues offer little benefit relative to conventional insulins in terms of glycaemic control or reduced hypoglycaemia. An editorial commentary from Austria endorsed this conclusion and recommended that the extensive promotion of insulin analogues is not justified. Insulin analogues should be reserved for use in selected patients, such as those with nocturnal hypoglycaemia. Cost effectiveness is considered in another paper and its authors feel that the routine use of insulin analogues, particularly the long-acting analogue in Type 2 diabetes, should be discouraged.
CMAJ 2009;180(4):385–97, 369–70 & 400–7.
We have noticed over the last year or so that when we request a serum creatinine we also receive a gratuitous eGFR. Is this a good thing? A debate in the Medical Journal of Australia reviews the pros and cons. A group of renal physicians are in favour alleging that the eGFR has been shown to provide unbiased and acceptably accurate estimates of measured GFR across a broad range of individuals with impaired kidney function. And furthermore is superior to measuring serum creatinine (SCr) concentration alone, more accurate than other prediction formulas (such as Cockcroft-Gault) in the setting of reduced kidney function, and more practical and reliable under most circumstances than measuring urinary creatinine clearance.
The other side incudes a clinician, a clinical pharmacologist and a biochemist. They agree that the eGFR is useful, but inaccurate because it assumes subjects are of average body size and similar lean body weight. They make the point that until the eGFR is validated they prefer the Cockcroft-Gault formula as the gold standard. As a bystander I believe it is useful as it reminds us that a normal serum creatinine, particularly in the elderly, can disguise renal impairment. But surely the Cockroft-Gault must be more accurate?
Med J Aust 2009;190:197–99 & 200–3.
This paper makes 10 points and I shall highlight 3 of them. Some medications can produce spuriously elevated serum creatinine levels. Apparently trimethoprim-sulfamethoxazole and the H2-blocker cimetidine are two commonly used drugs that decrease the secretion of creatinine. Famotidine, ranitidine and cefoxitin may also do this. The change is modest, reversible and not reflected in the blood urea test. And there is the point that phosphate-containing bowel preparations should be used with caution as phosphate nephropathy may occur. As we have dispensed with such this point is of historical interest only. And the other point, discussed in the preceding abstract, is that a “normal” serum creatinine level may not be normal.
The authors also discuss the eGFR and have the same reservations about its accuracy and validation. Nevertheless it does raise suspicion about the accuracy of the serum creatinine.
Mayo Clin Proc 2009;84(2):180–6.
In this paper an Israeli paediatric rheumatologist reviews two papers that suggest that only those children with very sore throats or those at high risk of sequelae should be treated with penicillin. From her perspective all proven or highly suspect probable streptococcal sore throats warrant full antibiotic treatment. Principally because treatment of pharyngitis with antibiotics reduces the risk of acute rheumatic fever eightfold.
But she also fears other sequelae such as Henoch Schonlein purpura, glomerulonephritis, recurrent uveitis and PANDAS (paediatric autoimmune neuropsychiatric disease associated with streptococcal infection). So back to the gold standard—10 days of penicillin—substantially the same message as offered in the Mayo Clinic abstract (NZMJ 3/10/08)
Acta Paediatrica 2009;98:434–36.
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