Journal of the New Zealand Medical Association, 25-May-2012, Vol 125 No 1355
Clinical practice guidelines have long recommended lithium as a first-line long-term treatment for bipolar disorder but its use has decreased, partly because of safety concerns. These are related to the drug’s low therapeutic index and the need to monitor its serum concentration and also monitor endocrine and renal function. This systematic review and meta-analysis aims to quantify the potential risks of lithium. They have included 385 studies in their analysis and their conclusions were:
“Lithium is associated with increased risk of reduced urinary concentrating ability, hypothyroidism, hyperparathyroidism, and weight gain. There is little evidence for a clinically significantly reduction in renal function in most patients, and the risk of end-stage renal failure is low. The risk of congenital malformations is uncertain; the balance of risks should be considered before lithium is withdrawn during pregnancy. Because of the consistent finding of a high prevalence of hyperparathyroidism, calcium concentrations should be checked before and after treatment”.
An accompanying editorial notes that this study provides timely clarification of the toxicity associated with lithium therapy and, on balance, reaffirms its role as a treatment of choice for bipolar disorder.
Lancet 2012;379:721–8 & 690–2.
There is evidence from many studies that demonstrate there is an increased risk of birth defects among births conceived with assisted reproductive technology as compared with births from spontaneous conception.
This paper seeks to elucidate whether this is a true association or if is explained by other underlying parental factors. Data obtained from over 300,000 births, including 6163 resulting from assisted conception, was analysed. The unadjusted odds ratio for birth defects involving assisted conception versus natural conception was 1.47. However, the increased risk associated with in vitro fertilisation was no longer significant after adjustment for parental factors.
N Engl J Med 2012;366:1803–13.
CT is now recognised as being superior to other tests, including abdominal ultrasound, in the diagnosis of acute appendicitis. However, many patients in whom appendicitis is suspected are children or young adults, and radiation exposure from CT is of particular concern in the population.
Hence this randomised trial which has evaluated the rate of negative (unnecessary) appendectomy after low-dose versus standard-dose abdominal CT in young adults with suspected appendicitis.
The researchers randomly assigned 891 patients with suspected appendicitis to either low-dose CT (444 patients) or standard-dose CT (447 patients). The median radiation dose in terms of dose-length product was 116 mGy·cm in the low-dose group and 521 mGy·cm in the standard-dose group. The negative appendectomy rates were 3.5% in the low-dose CT group and 3.2% in the standard-dose CT group.
The researchers conclude that low-dose CT was noninferior to standard-dose CT with respect to negative appendectomy rates in young adults with suspected appendicitis.
N Engl J Med 2012;366:1596–605.
Such monitoring is useful in those diabetes who are treated with insulin as they are at significant risk of hypoglycaemia or hyperglycaemia. This paper gets to grips with the usefulness of self monitoring in non-insulin treated type 2 diabetics. They reviewed 6 randomised trials and they report a small but statistically significant reduction in HbA1C levels at 6 months in those who have used self monitoring. The mean pooled reduction in HbA1C at 6 months was 9.6 mmol/L in the monitored group compared with 7.5 in the controls. They felt that the evidence was not convincing enough to support the routine use of self monitoring in such patients.
The author of this study note that screening for diabetic retinopathy is cost effective, although the current policy of screening every person with diabetes each year might not be necessary.
They have done a retrospective analysis of data from 49,763 subjects with type 2 diabetes mellitus and no evidence of diabetic retinopathy attending systematic screening provided by the Diabetic Retinopathy Screening Service for Wales between January 2005 and November 2009. They report the annual incidence of referable retinopathy remained low at 2.02 and 3.54 per 1000 people in the first and fourth follow-up year, respectively.
They conclude that these findings lend support to the use of risk stratification to define the most appropriate screening interval, with less frequent screening needed in people at low risk of developing retinopathy, therefore allowing more frequent screening in those at high risk. Those at higher risk seem to be those who have had diabetes for 10 years or more and those requiring insulin treatment.
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