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Non-invasive prenatal tests reduce false-positives
RESEARCHERS in the US have called for non-invasive maternal plasma cell-free DNA (cfDNA) testing to be incorporated into general obstetrics practice after finding that it performed better than standard screening to detect fetal autosomal aneuploidy. The research, published in the New England Journal of Medicine, found the cfDNA test to detect trisomies had a significantly lower false-positive rate and higher positive and negative predictive values than the standard method of biochemical assay and measurement of nuchal translucency in low-risk women. The blinded study included 1914 women undergoing routine obstetric care for singleton pregnancies, with the outcome determined on the basis of newborn physical examination. “With the results for trisomies 21 and 18 combined, the false positive rates were 4.2% for standard screening and 0.5% for cfDNA testing”, the researchers wrote. “If all pregnant women had undergone cfDNA testing as a primary screening method and if all women with positive results had undergone post-test counseling and had decided to undergo an invasive procedure, there would have been a relative reduction of 89% in the number of diagnostic invasive procedures required to confirm a positive screening result.” An accompanying editorial said a negative result on cfDNA screening “obviates the need for invasive testing and thus the discomfort and risk to the pregnancy incurred by such testing”.
Death risk increased in secondary thyroid cancer
SECONDARY malignancy status is an independent risk factor for decreased overall survival among adolescents and young adults (AYAs) diagnosed with thyroid cancer, according to research published in Cancer. While most thyroid cancers are primary, a subset are secondary malignant neoplasms arising in survivors of pediatric or other AYA malignancies. In a comparison study based on 12 years of data for 41 062 cases the researchers found that patients with secondary thyroid cancer were at an almost sevenfold increased risk of death compared to AYAs with primary thyroid cancer. Given that thyroid cancer was one of the five most common malignancies in AYAs the numbers were “not insignificant”, the researchers wrote, adding that “patients need to be counselled appropriately”. Primary thyroid cancers occurred more often in AYAs in their 20s compared to those aged 15–19 years or over the age of 30 years, where secondary thyroid cancers were more common. The researchers wrote that whether the increased risk of death in patients with secondary malignancies was a direct result of “previous cancer treatment, biological or environmental factors, or disparity in access to care” should be the subject of further study.
Lithium-associated renal disease on the rise
ALTHOUGH lithium-induced nephropathy (LiN) is an uncommon cause of end-stage renal disease (ESRD) it could be avoided with more careful monitoring of renal function and serum lithium levels in patients with bipolar disorder, according to the authors of research published in the MJA. The researchers found LiN contributed to 187 people commencing renal replacement therapy in Australia between 1991 and 2011, with the incidence rate increasing from 0.14 cases/million population/year in 1992–1996 to 0.78 cases in 2007–2011. LiN patients were more likely to be women, white, smokers and to have a higher body mass index, but were less likely to have undergone renal biopsy. LiN could be avoided by careful diagnosis of bipolar illness, restricted prescription of lithium, careful follow-up and improved record keeping, the researchers wrote. They suggested that renal function and serum lithium levels be monitored more frequently than every 6 months and “certainly more than every 12 months”, saying doctors should consider stopping lithium treatment and using another mood stabiliser if renal function in bipolar patients decreased over two consecutive readings. “The evidence suggests that ESRD occurs after long exposure to lithium, up to 23 years”, they wrote.
Bereavement increases cardiovascular events
A MARKED increase in cardiovascular events in older people the month after the death of their partner adds to evidence that bereavement is associated with a range of major cardiovascular events, according to research published in JAMA Internal Medicine. The matched cohort research included data from 401 UK general practices over 7 years for 30 447 patients aged 60–89 years who experienced partner bereavement and 83 588 non-bereaved patients. Within 30 days of their partner’s death, 50 of the bereaved group (0.16%) experienced a myocardial infarction (MI) or a stroke compared with 67 of the matched non-bereaved controls (0.08%). Increased risks in the first 90 days after bereavement were found for MI, stroke, non-MI acute coronary syndrome and pulmonary embolism in both men and women. The authors wrote that although the absolute contribution of bereavement to cardiovascular event rates was small because it was “unrepeated” and “relatively short-term” it was nevertheless “important and one element of a range of poor health outcomes after bereavement”. Possible causative factors included short-term changes in blood pressure, cortisol levels, heart rate variability, platelet activation and clotting factor levels, as well as neglect of health care needs like medication compliance. The authors concluded that “a better understanding of psychosocial factors associated with acute cardiovascular events may provide opportunities for prevention and improved clinical care”.
Dermatitis risk in baby wipes
A PRESERVATIVE used in disposable baby wipes, shampoos and sunscreens is causing an increasing number of cases of allergic contact dermatitis, according to a research letter published in the MJA. Methylisothiazolinone (MIT), used to prevent bacterial contamination, is also used in conditioners, body washes, moisturisers and deodorants, as well as in paints, cooling tower water and cutting oils. The Victorian researchers said they had included MIT in patch tests for allergies since 2011, following European reports of increased numbers of MIT contact allergy. They found that the rate of positive test reactions to MIT had increased from 3.5% in 2011 to 11.3% in 2013. “[MIT] is now the most common cause of allergic contact dermatitis (ACD) in our patient population”, they wrote. The authors wrote that parents using baby wipes on their children were experiencing contact dermatitis, “although it is likely that ACD involving the groin in children may not be diagnosed accurately”.