[RESEARCH] The impact of response to the results of diagnostic tests for malaria: cost-benefit analysis
Objective Rapid diagnostic tests for malaria seem cost effective in standard analyses, but these do not take account of clinicians’ response to test results. This study tested the impact of clinicians’ response to rapid diagnostic test or microscopy results on the costs and benefits of testing at different levels of malaria transmission and in different age groups.
Design Cost-benefit analysis using a decision tree model and clinical data on the effectiveness of diagnostic tests for malaria, their costs, and clinicians’ response to test results.
Setting Tanzania.
Methods Data were obtained from a clinical trial of 2425 patients carried out in three settings of varying transmission.
Results At moderate and low levels of malaria transmission, rapid diagnostic tests were more cost beneficial than microscopy, and both more so than presumptive treatment, but only where response was consistent with test results. At the levels of prescription of antimalarial drugs to patients with negative tests that have been found in observational studies and trials, neither test methodis likely to be cost beneficial, incurring costs 10-250% higher, depending on transmission rate, than would have been the case with fully consistent responses to all test results. Microscopy becomes more cost beneficial than rapid diagnostic tests when its sensitivity under operational conditions approaches that of rapid diagnostic tests.
Conclusions Improving diagnostic methods, including rapid diagnostic tests, can reduce costs and enhance the benefits of effective antimalarial drugs, but only if the consistency of response to test results is also improved. Investing in methods to improve rational response to tests is essential. Economic evaluations of diagnostic tests should take into account whether clinicians’ response is consistent with test results.
[RESEARCH] Limitations of rapid HIV-1 tests during screening for trials in Uganda: diagnostic test accuracy study
Objective To evaluate the limitations of rapid tests for HIV-1.
Design Diagnostic test accuracy study.
Setting Rural Rakai, Uganda.
Participants 1517 males aged 15-49 screened for trials of circumcision for HIV prevention.
Main outcome measures Sensitivity, specificity, negative predictive values, and positive predictive values of an algorithm using three rapid tests for HIV, compared with the results of enzyme immunoassay and western blotting as the optimal methods.
Results Rapid test results were evaluated by enzyme immunoassay and western blotting. Sensitivity was 97.7%. Among 639 samples where the strength of positive bands was coded if the sample showed positivity for HIV, the algorithm had low specificity (94.1%) and a low positive predictive value (74.0%). Exclusion of 37 samples (5.8%) with a weak positive band improved the specificity (99.6%) and positive predictive value (97.7%).
Conclusion Weak positive bands on rapid tests for HIV should be confirmed by enzyme immunoassay and western blotting before disclosing the diagnosis. Programmes using rapid tests routinely should use standard serological assays for quality control.
Trial registration Clinical Trials NCT00425984.
Insulin "Bong" produces mixed results
Filed under: Type 2, Drugs, Research
I apologize for covering a topic that may have very well been covered already a few weeks ago, but the way I see it, if
the entries on this page change too quickly for the bloggers to keep up, it must be extra tough for the readers. That all being said, I wanted to point out the mixed results of a recent study on inhaled insulin (or the insulin bong, as I like to call it).
For people with type 2 diabetes, taking extra insulin during mealtimes is a necessary step in helping to regulated blood glucose levels. These doses are taken in addition to baseline insulin that is taken throughout the day and night. What researchers at the ECRI Institute have discovered is that inhaled insulin may improve blood sugar control for people with type 2 just as well as short-acting insulin taken by injection.
After a three-month period, the researchers found the inhaled insulin to produce equally as effective results in patients than insulin shots. The tricky part, however, is that the inhaled insulin seemed to be a bit problematic for users who experienced low blood sugar levels -- hypoglycemia.
Despite the mostly positive results, inhaled insulin still gets mixed reviews from researchers. Not only is its problem dealing with hypo a...well, a problem, but speculation also surrounds the long-term effect of inhaled insulin on the lungs.
[RESEARCH] Effect of high throughput RHD typing of fetal DNA in maternal plasma on use of anti-RhD immunoglobulin in RhD negative pregnant women: prospective feasibility study
Objectives To assess the feasibility of applying a high throughput method, with an automated robotic technique, for predicting fetal RhD phenotype from fetal DNA in the plasma of RhD negative pregnant women to avoid unnecessary treatment with anti-RhD immunoglobulin.
Design Prospective comparison of fetal RHD genotype determined from fetal DNA in maternal plasma with the serologically determined fetal RhD phenotype from cord blood.
Setting Antenatal clinics and antenatal testing laboratories in the Midlands and north of England and an international blood group reference laboratory.
Participants Pregnant women of known gestation identified as RhD negative by an antenatal testing laboratory. Samples from 1997 women were taken at or before the 28 week antenatal visit.
Main outcome measures Detection rate of fetal RhD from maternal plasma, error rate, false positive rate, and the odds of being affected given a positive result.
Results Serologically determined RhD phenotypes were obtained from 1869 cord blood samples. In 95.7% (n=1788) the correct fetal RhD phenotype was predicted by the genotyping tests. In 3.4% (n=64) results were either unobtainable or inconclusive. A false positive result was obtained in 0.8% (14 samples), probably because of unexpressed or weakly expressed fetal RHD genes. In only three samples (0.2%) were false negative results obtained. If these results had been applied as a guide to treatment, only 2% of the women would have received anti-RhD unnecessarily, compared with 38% without the genotyping.
Conclusions High throughput RHD genotyping of fetuses in all RhD negative women is feasible and would substantially reduce unnecessary administration of anti-RhD immunoglobulin to RhD negative pregnant women with an RhD negative fetus.
[RESEARCH] Long term risk of invasive cancer after treatment for cervical intraepithelial neoplasia grade 3: population based cohort study
Objective To study the long term risk of invasive cancer of the cervix or vagina after treatment for cervical intraepithelial neoplasia grade 3.
Design Prospective cohort study.
Setting Swedish cancer registry.
Participants All women in Sweden with severe dysplasia or cervical carcinoma in situ (equivalent to cervical intraepithelial neoplasia grade 3) treated during 1958-2002 (n=132 493) contributing 2 315 724 woman years.
Main outcome measures Standardised incidence ratios with risk of cancer in the Swedish general female population as reference, and relative risks in multivariable log-linear regression model, with internal references.
Results Women with previous cervical intraepithelial neoplasia grade 3 had an increased risk of invasive cervical cancer compared with the general female population (standardised incidence ratio 2.34, 95% confidence interval 2.18 to 2.50). The increased risk showed a decreasing trend with time since diagnosis for women treated later than 1970 but the risk was still increased after 25 years. An effect of age was found, with an accentuated increase in risk for women aged more than 50. The excess risk for cervical cancer associated with previous cervical intraepithelial neoplasia grade 3 has steadily increased since 1958. For vaginal cancer the standardised incidence ratio was 6.82 (5.61 to 8.21) but this decreased to 2.65 after 25 years. Adjustments in the multivariable log-linear regression model did not substantially alter these results.
Conclusions Women previously treated for cervical intraepithelial neoplasia grade 3 are at an increased risk of developing invasive cervical cancer and vaginal cancer. This risk has increased since the 1960s and is accentuated in women aged more than 50. The risk is still increased 25 years after treatment.
[RESEARCH] Adherence to Mediterranean diet and risk of developing diabetes: prospective cohort study
Objective To assess the relation between adherence to a Mediterranean diet and the incidence of diabetes among initially healthy participants.
Design Prospective cohort study with estimates of relative risk adjusted for sex, age, years of university education, total energy intake, body mass index, physical activity, sedentary habits, smoking, family history of diabetes, and personal history of hypertension.
Setting Spanish university department.
Participants 13 380 Spanish university graduates without diabetes at baseline followed up for a median of 4.4 years.
Main outcome measures Dietary habits assessed at baseline with a validated 136 item food frequency questionnaire and scored on a nine point index. New cases of diabetes confirmed through medical reports and an additional detailed questionnaire posted to those who self reported a new diagnosis of diabetes by a doctor during follow-up. Confirmed cases of type 2 diabetes.
Results Participants who adhered closely to a Mediterranean diet had a lower risk of diabetes. The incidence rate ratios adjusted for sex and age were 0.41 (95% confidence interval 0.19 to 0.87) for those with moderate adherence (score 3-6) and 0.17 (0.04 to 0.75) for those with the highest adherence (score 7-9) compared with those with low adherence (score <3). In the fully adjusted analyses the results were similar. A two point increase in the score was associated with a 35% relative reduction in the risk of diabetes (incidence rate ratio 0.65, 0.44 to 0.95), with a significant inverse linear trend (P=0.04) in the multivariate analysis.
Conclusion Adherence to a Mediterranean diet is associated with a reduced risk of diabetes.
[RESEARCH] Case-control study of self reported genitourinary infections and risk of gastroschisis: findings from the national birth defects prevention study, 1997-2003
Objective To assess the association between genitourinary infections in the month before conception to the end of the first trimesterand gastroschisis.
Design Case-control study with self reported infections from a computer assisted telephone interview.
Setting National birth defects prevention study, a multisite, population based study including 10 surveillance systems for birth defects in the United States.
Participants Mothers of 505 offspring with gastroschisis and 4924 healthy liveborn infants as controls.
Main outcome measure Adjusted odds ratios for gastroschisis with 95% confidence intervals.
Results About 16% (n=81) of case mothers and 9% (n=425) of control mothers reported a genitourinary infection in the relevant time period; 4% (n=21) and 2% (n=98) reported a sexually transmitted infection and 13% (n=67) and 7% (n=338) reported a urinary tract infection, respectively. Case mothers aged <25 years reported higher rates of urinary tract infection alone and in combination with a sexually transmitted infection compared with control mothers. In women who reported both types of infection, there was a greater risk of gastroschisis in offspring (adjusted odds ratio 4.0, 95% confidence interval 1.4 to 11.6).
Conclusion There is a significant association between self reported urinary tract infection plus sexually transmitted infection just before conception and in early pregnancy and gastroschisis.
[RESEARCH] Risk of respiratory morbidity in term infants delivered by elective caesarean section: cohort study
Objective To investigate the association between elective caesarean sections and neonatal respiratory morbidity and the importance of timing of elective caesarean sections.
Design Cohort study with prospectively collected data from the Aarhus birth cohort, Denmark.
Setting Obstetric department and neonatal department of a university hospital in Denmark.
Participants All liveborn babies without malformations, with gestational ages between 37 and 41 weeks, and delivered between 1 January 1998 and 31 December 2006 (34 458 babies).
Main outcome measures Respiratory morbidity (transitory tachypnoea of the newborn, respiratory distress syndrome, persistent pulmonary hypertension of the newborn) and serious respiratory morbidity (oxygen therapy for more than two days, nasal continuous positive airway pressure, or need for mechanical ventilation).
Results 2687 infants were delivered by elective caesarean section. Compared with newborns intended for vaginal delivery, an increased risk of respiratory morbidity was found for infants delivered by elective caesarean section at 37 weeks’ gestation (odds ratio 3.9, 95% confidence interval 2.4 to 6.5), 38 weeks’ gestation (3.0, 2.1 to 4.3), and 39 weeks’ gestation (1.9, 1.2 to 3.0). The increased risks of serious respiratory morbidity showed the same pattern but with higher odds ratios: a fivefold increase was found at 37 weeks (5.0, 1.6 to16.0). These results remained essentially unchanged after exclusion of pregnancies complicated by diabetes, pre-eclampsia, and intrauterine growth retardation, or by breech presentation.
Conclusion Compared with newborns delivered vaginally or by emergency caesarean sections, those delivered by elective caesarean section around term have an increased risk of overall and serious respiratory morbidity. The relative risk increased with decreasing gestational age.
[RESEARCH] Main morbidities recorded in the women's international study of long duration oestrogen after menopause (WISDOM): a randomised controlled trial of hormone replacement therapy in postmenopausal women
Objective To assess the long term risks and benefits of hormone replacement therapy (combined hormone therapy versus placebo, and oestrogen alone versus combined hormone therapy).
Design Multicentre, randomised, placebo controlled, double blind trial.
Setting General practices in UK (384), Australia (91), and New Zealand (24).
Participants Postmenopausal women aged 50-69 years at randomisation. At early closure of the trial, 56 583 had been screened, 8980 entered run-in, and 5692 (26% of target of 22 300) started treatment.
Interventions Oestrogen only therapy (conjugated equine oestrogens 0.625 mg orally daily) or combined hormone therapy (conjugated equine oestrogens plus medroxyprogesterone acetate 2.5/5.0 mg orally daily). Ten years of treatment planned.
Main outcome measures Primary outcomes: major cardiovascular disease, osteoporotic fractures, and breast cancer. Secondary outcomes: other cancers, death from all causes, venous thromboembolism, cerebrovascular disease, dementia, and quality of life.
Results The trial was prematurely closed during recruitment, after a median follow-up of 11.9 months (interquartile range 7.1-19.6, total 6498 women years) in those enrolled, after the publication of early results from the women's health initiative study. The mean age of randomised women was 62.8 (SD 4.8) years. When combined hormone therapy (n=2196) was compared with placebo (n=2189), there was a significant increase in the number of major cardiovascular events (7 v 0, P=0.016) and venous thromboembolisms (22 v 3, hazard ratio 7.36 (95% CI 2.20 to 24.60)). There were no statistically significant differences in numbers of breast or other cancers (22 v 25, hazard ratio 0.88 (0.49 to 1.56)), cerebrovascular events (14 v 19, 0.73 (0.37 to 1.46)), fractures (40 v 58, 0.69 (0.46 to 1.03)), and overall deaths (8 v 5, 1.60 (0.52 to 4.89)). Comparison of combined hormone therapy (n=815) versus oestrogen therapy (n=826) outcomes revealed no significant differences.
Conclusions Hormone replacement therapy increases cardiovascular and thromboembolic risk when started many years after the menopause. The results are consistent with the findings of the women's health initiative study and secondary prevention studies. Research is needed to assess the long term risks and benefits of starting hormone replacement therapy near the menopause, when the effect may be different.
Trial registration Current Controlled Trials ISRCTN 63718836
Running over the same old ground: exercise and diabetes
Filed under: Type 2, Lifestyle, Exercise, Daily News
Oh yawn, I thought to myself this morning. Upon turning on National Public Radio, I immediately heard what seems to be yet another report on diabetics and exercise. According to the results of a new study, the majority of people with Type 2 diabetes or at risk for it fail to follow through on their doctors' advice to get moving and get some good old-fashioned exercise to ward off the disease - or at least slow its progress. The study comes courtesy of a team of researchers at the University of Colorado, Denver. It's a sizable study, involving over 22,000 patients. The results are being published in Diabetes Care (February 2007) and basically conclude that fewer than forty percent of those advised to get exercise actually do so. Moreover, those most at risk are in fact the least likely to heed exercise advice. Dr. Elaine Morrato, who led both this study and an earlier one on a similar topic, says "People should exercise more, that story is out. What we're saying is, 'Here's a high-risk population that can benefit from exercise, and they're even less likely to exercise.'" Now, I hate to be a grumpy naysayer, but (to use an exercise-related metaphor) isn't this just a case of running over the same old ground? Is this study really contributing anything new? According to the NPR report, Morrato goes on to say that the results are "very pessimistic," but that she does not know the answer to what is perhaps the real question: how to change peoples' behavior. We already know there is a T2 diabetes epidemic going on. We already know that obesity and inactivity are to blame. Instead of studying the issue over and over, from every conceivable angle, shouldn't researchers be focusing on how to stop this national health train wreck that we're seeing? Am I being unreasonable? You tell me.