Placental alpha-microglobulin-1 and combined traditional diagnostic test: a cost-benefit analysis.

OBJECTIVE: We sought to evaluate if the placental alpha-microglobulin (PAMG)-1 test vs the combined traditional diagnostic test (CTDT) of pooling, nitrazine, and ferning would be a cost-beneficial screening strategy in the setting of potential preterm premature rupture of membranes. STUDY DESIGN: A decision analysis model was used to estimate the economic impact of PAMG-1 test vs the CTDT on preterm delivery costs from a societal perspective. Our primary outcome was the annual net cost-benefit per person tested. Baseline probabilities and costs assumptions were derived from published literature. We conducted sensitivity analyses using both deterministic and probabilistic models. Cost estimates reflect 2013 US dollars. RESULTS: Annual net benefit from PAMG-1 was $20,014 per person tested, while CTDT had a net benefit of $15,757 per person tested. If the probability of rupture is <38%, PAMG-1 will be cost-beneficial with an annual net benefit of $16,000-37,000 per person tested, while CTDT will have an annual net benefit of $16,000-19,500 per person tested. If the probability of rupture is >38%, CTDT is more cost-beneficial. Monte Carlo simulations of 1 million trials selected PAMG-1 as the optimal strategy with a frequency of 89%, while CTDT was only selected as the optimal strategy with a frequency of 11%. Sensitivity analyses were robust. CONCLUSION: Our cost-benefit analysis provides the economic evidence for the adoption of PAMG-1 in diagnosing preterm premature rupture of membranes in uncertain presentations and when CTDT is equivocal at 34 to <37 weeks' gestation.

Neural encoding of sound duration persists in older adults.

Speech perception depends strongly on precise encoding of the temporal structure of sound. Although behavioural studies suggest that communication problems experienced by older adults may entail deficits in temporal acuity, much is unknown about the effects of age on the neural mechanisms underlying the encoding of sound duration. In this study, we measured neuromagnetic auditory evoked responses in young, middle-aged and older healthy participants listening to sounds of various durations. The time courses of cortical activity from bilateral sources in superior temporal planes showed specific differences related to the sound offsets indicating the neural representation of onset and offset markers as one dimension of the neural code for sound duration. Model free MEG source analysis identified brain areas specifically responding with an increase in activity to increases in sound duration in the left anterior insula, right inferior frontal, right middle temporal, and right post-central gyri in addition to bilateral supra-temporal gyri. Sound duration-related changes in cortical responses were comparable in all three age groups despite age-related changes in absolute response magnitudes. The results demonstrated that early cortical encoding of the temporal structure of sound presented in silence is little or not affected by normal aging.

Prophylactic use of negative pressure wound therapy after cesarean delivery.

OBJECTIVE: To evaluate the economic benefit of prophylactic negative pressure wound therapy on a closed laparotomy incision after cesarean delivery in comparison with standard postoperative dressing. METHODS: We designed a decision-analytic model from a third-party payer's perspective to determine the cost-benefit of prophylactic application of negative pressure wound therapy compared with standard postoperative dressing on a closed laparotomy incision after cesarean delivery. Our primary outcome measure was the expected value of the cost per strategy. Baseline probabilities and cost assumptions were derived from published literature. We conducted sensitivity analyses using both deterministic and probabilistic models. Cost estimates reflect 2014 U.S. dollars. RESULTS: Under our baseline parameters, standard postoperative dressing was the preferred strategy. Standard postoperative dressing and prophylactic negative pressure wound therapy cost $547 and $804 per strategy, respectively. Sensitivity analyses showed that prophylactic negative pressure wound therapy can be cost-beneficial if it is priced below $192; standard postoperative dressing is the preferred strategy among patients with surgical site infection rate of 14% or less. If surgical site infection rates are greater than 14%, prophylactic negative pressure wound therapy could be cost-beneficial depending on the degree of reduction in surgical site infections. At a surgical site infection rate of 30%, the rate must be reduced by 15% for negative pressure wound therapy to become the preferred strategy. Monte Carlo simulation of 1,000 patients in 1 million trials showed that standard postoperative dressing was the preferred cost-beneficial strategy with a frequency of 85%. CONCLUSION: Our cost-benefit analysis provides economic evidence suggesting that negative pressure wound therapy should not be used on closed laparotomy incisions of patients with low risk of postcesarean delivery surgical site infections. However, among patients with a high risk of surgical site infections, prophylactic negative pressure wound therapy is potentially cost-beneficial.