Cost-effectiveness of behavioral and pelvic floor muscle therapy combined with midurethral sling surgery vs surgery alone among women with mixed urinary incontinence: results of the Effects of Surgical Treatment Enhanced With Exercise for Mixed Urinary Incontinence randomized trial.

BACKGROUND: Urinary incontinence is prevalent among women, and it has a substantial economic impact. Mixed urinary incontinence, with both stress and urgency urinary incontinence symptoms, has a greater adverse impact on quality of life and is more complex to treat than either stress or urgency urinary incontinence alone. Studies evaluating the cost-effectiveness of treating both the stress and urgency urinary incontinence components simultaneously are lacking. OBJECTIVE: Cost-effectiveness was assessed between perioperative behavioral and pelvic floor muscle therapies combined with midurethral sling surgery and midurethral sling surgery alone for the treatment of women with mixed urinary incontinence. The impact of baseline severe urgency urinary incontinence symptoms on cost-effectiveness was assessed. STUDY DESIGN: This prospective economic evaluation was performed concurrently with the Effects of Surgical Treatment Enhanced with Exercise for Mixed Urinary Incontinence randomized trial that was conducted from October 2013 to April 2016. Participants included 480 women with moderate-to-severe stress and urgency urinary incontinence symptoms and at least 1 stress urinary incontinence episode and 1 urgency urinary incontinence episode on a 3-day bladder diary. The primary within-trial analysis was from the healthcare sector and societal perspectives, with a 1-year time horizon. Costs were in 2019 US dollars. Effectiveness was measured in quality-adjusted life-years and reductions in urinary incontinence episodes per day. Incremental cost-effectiveness ratios of combined treatment vs midurethral sling surgery alone were calculated, and cost-effectiveness acceptability curves were generated. Analysis was performed for the overall study population and subgroup of women with Urogenital Distress Inventory irritative scores of ≥50th percentile. RESULTS: The costs for combined treatment were higher than the cost for midurethral sling surgery alone from both the healthcare sector perspective ($5100 [95% confidence interval, $5000-$5190] vs $4470 [95% confidence interval, $4330-$4620]; P<.01) and the societal perspective ($9260 [95% confidence interval, $8590-$9940] vs $8090 [95% confidence interval, $7630-$8560]; P<.01). There was no difference between combined treatment and midurethral sling surgery alone in quality-adjusted life-years (0.87 [95% confidence interval, 0.86-0.89] vs 0.87 [95% confidence interval, 0.86-0.89]; P=.90) or mean reduction in urinary incontinence episodes per day (-4.76 [95% confidence interval, -4.51 to 5.00] vs -4.50 [95% confidence interval, -4.25 to 4.75]; P=.13). When evaluating the overall study population, from both the healthcare sector and societal perspectives, midurethral sling surgery alone was superior to combined treatment. The probability that combined treatment is cost-effective compared with midurethral sling surgery alone is ≤28% from the healthcare sector and ≤19% from the societal perspectives for a willingness-to-pay value of ≤$150,000 per quality-adjusted life-years. For women with baseline Urogenital Distress Inventory irritative scores of ≥50th percentile, combined treatment was cost-effective compared with midurethral sling surgery alone from both the healthcare sector and societal perspectives. The probability that combined treatment is cost-effective compared with midurethral sling surgery alone for this subgroup is ≥90% from both the healthcare sector and societal perspectives, at a willingness-to-pay value of ≥$150,000 per quality-adjusted life-years. CONCLUSION: Overall, perioperative behavioral and pelvic floor muscle therapies combined with midurethral sling surgery was not cost-effective compared with midurethral sling surgery alone for the treatment of women with mixed urinary incontinence. However, combined treatment was of good value compared with midurethral sling surgery alone for women with baseline severe urgency urinary incontinence symptoms.

Integrating field and laboratory approaches for ripple development in mixed sand-clay-EPS.

The shape and size of sedimentary bedforms play a key role in the reconstruction of sedimentary processes in modern and ancient environments. Recent laboratory experiments have shown that bedforms in mixed sand-clay develop at a slower rate and often have smaller heights and wavelengths than equivalent bedforms in pure sand. This effect is generally attributed to cohesive forces that can be of physical origin, caused by electrostatic forces of attraction between clay minerals, and of biological origin, caused by 'sticky' extracellular polymeric substances (EPS) produced by micro-organisms, such as microalgae (microphytobenthos) and bacteria. The present study demonstrates, for the first time, that these laboratory experiments are a suitable analogue for current ripples formed by tidal currents on a natural mixed sand-mud-EPS intertidal flat in a macrotidal estuary. Integrated hydrodynamic and bed morphological measurements, collected during a spring tide under weak wave conditions near Hilbre Island (Dee Estuary, north-west England, UK), reveal a statistically significant decrease in current ripple wavelength for progressively higher bed mud and EPS contents, and a concurrent change from three-dimensional linguoid to two-dimensional straight-crested ripple planform morphology. These results agree well with observations in laboratory flumes, but the rate of decrease of ripple wavelength as mud content increased was found to be substantially greater for the field than the laboratory. Since the formation of ripples under natural conditions is inherently more complex than in the laboratory, four additional factors that might affect current ripple development in estuaries, but which were not accounted for in laboratory experiments, were explored. These were current forcing, clay type, pore water salinity and bed EPS content. These data illustrate that clay type alone cannot explain the difference in the rate of decrease in ripple wavelength, because the bed clay contents were too low for clay type to have had a measurable effect on bedform development. Accounting for the difference in current forcing between the field and experiments, and therefore the relative stage of development with respect to equilibrium ripples, increases the difference between the ripple wavelengths. The presence of strongly cohesive EPS in the current ripples on the natural intertidal flat might explain the majority of the difference in the rate of decrease in ripple wavelength between the field and the laboratory. The effect of pore water salinity on the rate of bedform development cannot be quantified at present, but salinity is postulated herein to have had a smaller influence on the ripple wavelength than bed EPS content. The common presence of clay and EPS in many aqueous sedimentary environments implies that a re-assessment of the role of current ripples and their primary current lamination in predicting and reconstructing flow regimes is necessary, and that models that are valid for pure sand are an inappropriate descriptor for more complex mixed sediment. This study proposes that this re-assessment is necessary at all bed clay contents above 3%.

The role of biophysical cohesion on subaqueous bed form size.

Biologically active, fine-grained sediment forms abundant sedimentary deposits on Earth's surface, and mixed mud-sand dominates many coasts, deltas, and estuaries. Our predictions of sediment transport and bed roughness in these environments presently rely on empirically based bed form predictors that are based exclusively on biologically inactive cohesionless silt, sand, and gravel. This approach underpins many paleoenvironmental reconstructions of sedimentary successions, which rely on analysis of cross-stratification and bounding surfaces produced by migrating bed forms. Here we present controlled laboratory experiments that identify and quantify the influence of physical and biological cohesion on equilibrium bed form morphology. The results show the profound influence of biological cohesion on bed form size and identify how cohesive bonding mechanisms in different sediment mixtures govern the relationships. The findings highlight that existing bed form predictors require reformulation for combined biophysical cohesive effects in order to improve morphodynamic model predictions and to enhance the interpretations of these environments in the geological record.

The pervasive role of biological cohesion in bedform development.

Sediment fluxes in aquatic environments are crucially dependent on bedform dynamics. However, sediment-flux predictions rely almost completely on clean-sand studies, despite most environments being composed of mixtures of non-cohesive sands, physically cohesive muds and biologically cohesive extracellular polymeric substances (EPS) generated by microorganisms. EPS associated with surficial biofilms are known to stabilize sediment and increase erosion thresholds. Here we present experimental data showing that the pervasive distribution of low levels of EPS throughout the sediment, rather than the high surficial levels of EPS in biofilms, is the key control on bedform dynamics. The development time for bedforms increases by up to two orders of magnitude for extremely small quantities of pervasively distributed EPS. This effect is far stronger than for physical cohesion, because EPS inhibit sand grains from moving independently. The results highlight that present bedform predictors are overly simplistic, and the associated sediment transport processes require re-assessment for the influence of EPS.