medical news in review: July 8-14, 2012
MedWire News: A round-up of select stories of interest to US physicians from the Merck Medicus Medical News wire.
More TZD woes
In a systematic review and meta-analysis, Jeffrey Johnson and colleagues from the University of Alberta in Edmonton, Canada, found that patients who had ever used a thiazolidinedione (TZD) had a significant 15% increased risk for bladder cancer compared with those who had never used one. Patients who had ever used pioglitazone, specifically, had a 22% increased bladder cancer risk.
Previous studies have linked another TZD, rosiglitazone, to increased risk for cardiovascular disease.
The current analysis included data from four randomized, controlled trials, five cohort studies, and one case-control study that collectively included over 2.6 million people with Type 2 diabetes. Of these, 3643 had newly diagnosed bladder cancer, for an overall incidence of 53.1 per 100 000 person-years.
Johnson and team explain that people with Type 2 diabetes have a 40% increased risk for bladder cancer, which is thought to be a result of hyperinsulinemia, whereby elevated insulin levels stimulate insulin receptors on neoplastic cells, promoting cancer growth and division.
Exogenous insulin and other glucose-lowering medications such as sulfonylureas, metformin, and thiazolidinediones, may further modify the risk, they add.
"Although the absolute risk of bladder cancer associated with pioglitazone was small, other evidence-based treatments for Type 2 diabetes may be equally effective and do not carry a risk of cancer," Johnson and co-authors remark in CMAJ.
The team concludes: "Future research is required to improve our understanding and should include large population-based cohort studies involving individuals with Type 2 diabetes; include a reference group of individuals without diabetes; have a minimum dose and duration of exposure; and account for important risk factors for bladder cancer (eg, smoking status and history of bladder disease)."
US kids standing sporting chance of athletic injury
Injuries from athletic sports such as sprinting, long-distance running, and hurdles, are on the increase in children and adolescents, report US researchers.
Lara McKenzie (The Ohio State University, Columbus) and colleagues found that the annual number of athletics or track-related injuries in 10-18 year olds increased by 36.3% between 1991 and 2008, from 7702to 10,496.
The most common types of injury over this period were sprains and/or strains, at 52%, and fractures or dislocations, at 17%, they report in The Physician and Sports medicine.
Of sprinting, cross-country, running, hurdles, relays, stretching and/or drills, and "other" activities, the most common activity at time of injury was running, at 59%, followed by hurdles, at 23%.
There was a gender difference in the most common injuries sustained, with boys being more likely to sustain pelvic injuries and girls ankle injuries. The students' ages also influenced the type of injury they had.
"We found that the most commonly injured body parts varied across activity and across age group. For instance, elementary students were more likely to sustain upper extremity injuries while high school students were more likely to sustain lower leg injuries," said McKenzie.
Common injury types also varied by sport. For example, hurdling was more likely to result in a head or upper extremity injury, and sprinting in an injury to the pelvis or upper leg.
BP variability signals stroke risk
Analysis of data from the Women's Health Initiative (WHI) supports the contention that variability in a person's blood pressure (BP) affects their risk for stroke.
The analysis, which appears in Hypertension, included 58,228 postmenopausal women who had 997 strokes during a median 5.4 years of follow up. The annual stroke rate rose in line with the variability in the women's visit-to-visit BP (ie, the standard deviation [SD] of their average BP during follow-up), from 0.20% for a SD of less than 6 mmHg to 0.49% for a SD of 13 mmHg or more.
After accounting for a raft of baseline variables and average BP, heart rate, and antihypertensive medication use during follow up, this equated to a 16% increase in stroke risk for each 5 mmHg rise in BP variability.
The association remained significant after Daichi Shimbo (Columbia University Medical Center, New York, USA) and team further adjusted for increases in average BP over time (by calculating the SD about the regression line), at a 12% increased risk per 5 mmHg rise.
Consistent with previous findings of Peter Rothwell (John Radcliffe Hospital, Oxford, UK) and colleagues, Shimbo et al found the strongest effect of BP variability to be among women with relatively low average systolic BP - below 120 mmHg.
Ambulance crews fail to notify ED of stroke arrivals
In other stroke-related news, two studies from the Get With The Guidelines-Stroke initiative show that the emergency medical services (EMS) often fail to notify hospitals of an incoming stroke patient, despite the clear positive effect on acute stroke treatment.
Prenotification occurred for just two-thirds of the 371,988 patients in the studies, and the rate increased only slightly between 2003 and 2011, from 58.0% to 67.3%.
"Despite national guidelines recommending pre-notification by EMS for acute stroke patients, it's disappointing that there's been little improvement," said Gregg Fonarow (University of California, Los Angeles, USA), lead author of both studies, in a press statement.
After accounting for confounders, prenotification by the EMS resulted in a significant 10.2% absolute increase in the proportion of patients who underwent imaging within 25 minutes of hospital arrival, a 3.3% increase in the proportion who underwent thrombolysis within 1 hour of arrival, and a 9.6% increase in the proportion who received thrombolysis within 3 hours of symptom onset (among those who arrived within 2 hours).
Prenotification by the EMS did not influence patients' risk for complications, show the findings in Circulation: Cardiovascular Quality and Outcomes.
The other study, published in the Journal of the American Heart Association, shows wide variation in EMS prenotification rates, with hospital-specific rates ranging from 0% to 100% and state-specific rates ranging from 19.7% in Washington, DC, to 93.4% in Montana.
"The large variations by state and hospital are really striking and should be a concern because the potential for ideal patient care isn't being met," said Fonarow.
The likelihood for EMS prenotification fell with increasing patient age and was reduced if patients were Black, had diabetes, previous vascular disease, or previous stroke.
More selective colon cancer screening urged
Updated guidance from a US task force stresses the need for targeted, high-quality follow-up screening in patients who have undergone colonoscopy or polyp removal, in an effort to cut down on unnecessary repeat procedures.
The new guidelines from the US Multi-Society Task Force (MSTF) on Colorectal Cancer, published in Gastroenterology, reflect evidence that has emerged since the MSTF's previous report in 2006. In particular, the authors hope the guidance will give doctors confidence to lengthen surveillance intervals in low-risk patients, something that until now they seem reluctant to do.
The report by David Lieberman (Oregon Health and Science University, Portland, USA) and colleagues, provides an assessment of the evidence and recommendations for screening based on the number, size, and histology of polyps.
Studies published since 2006 support 10-year screening in patients who have had no adenomas or polyps or those with only distal hyperplastic polyps at baseline, which are considered low-risk adenomas. Contrary to the guidelines, however, a recent survey found that 25% of patients with no adenomas at baseline had undergone a repeat colonoscopy within 5 years, while over 40% with small adenomas had undergone one or more screening procedures.
The study also supported previous recommendations for high-risk adenomas, for example, those with multiple lesions and those with villous histology, which require shorter screening intervals.
The authors note the need to balance overscreening with underscreening: "Overutilization exposes patients to the cost and risk of unnecessary procedures. Underutilization could result in higher-risk patients developing cancer."
For the first time, the task force provides guidance on screening after detection of serrated polyps, which are precursors to hypermethylated cancers. Sessile serrated polyps of at least 10 mm in size or with cytologic dysplasia should be managed as a high-risk adenoma, say the guidelines. However, the evidence for this is still limited and of low quality, highlighting a need for further research.
More reason to hold the hormones in menopause
Researchers have found further evidence to show that menopausal hormone therapy (MHT) increases the risk for high blood pressure (BP) in postmenopausal women.
The association between MHT use and high BP diminished with increasing age in the study, which shows that age is a significant predictor for the development of high BP, comment the authors in PLoS One.
Joanne Lind (University of Western Sydney, New South Wales, Australia) and team found that MHT use was associated with a 59% increased risk for high BP in women younger than 56 years of age, a 58% increased risk for those aged 56-61 years, and a 26% increased risk for those aged 62-70 years.
However, in women aged 71 years and older, there was no significant association between MHT use and high BP.
Moreover, there was no statistically significant difference in the odds for having high BP between past and current users of MHT in any age group.
The duration of MHT use was significantly associated with the risk for having high BP, with women who had used MHT for longer time periods having greater increases in risk.
Indeed, among women younger than 56 years who had used MHT for less than 2 years, the risk for high BP was increased by just 0.07%, whereas for those who had used it for more than 10 years, the risk was increased more than threefold.
The findings of the current study, conducted in 43,405 postmenopausal women, are in line with current FDA recommendations that MHT should be limited to the shortest possible duration consistent with treatment goals.
By Neil Osterweil