Demonstrating effectiveness—the concept of numbers‐needed‐to‐treat

When assessing a health-care intervention the main question is—does it work? Often, a more difficult question needs to be answered—how well does it work? Systematic reviews and meta-analyses help to provide answers to both questions. Too often though, the results are expressed in a way that leaves the reader asking, ‘what is the result?’ Numbers-needed-to-treat is a simple method for conveying the answers. It can be applied to any chosen clinical outcome with dichotomous data, and the results can be understood by doctor, patient and the public. This paper discusses the concept of numbers-needed-to-treat and gives worked examples using trials in H. pylori eradication and lowering of serumcholesterol.     

A study of amylopectin sulfate and bile damage to the gastric mucosal barrier

The protective action against mucosal damage of a sulfated polysaccharide, amylopectin sulfate, was examined in the Heidenhain pouches of 3 dogs. The net fluxes of hydrogen and sodium ion were measured before, during, and after exposure of the mucosa to a 10 mM bile acid solution at pH 2. The potential difference (PD) across gastric mucosa was measured during the experiments. Hydrogen ion back-diffusion from and sodium ion gain by the pouch were significantly increased by bile; there was also a simultaneous fall in PD. However, when the pouches were first treated with a 2% aqueous solution of amylopectin sulfate, the net increase in the flux of H⁺ and Na⁺ was significantly less after exposure to bile. The fall in PD was also significantly less. These results suggest that amylopectin sulfate protects gastric mucosa against the damaging effect of bile.     

Who foregoes survivor protection in employer-sponsored pension annuities?

PURPOSE: Retirees in traditional pension plans must generally choose between single life annuities, which provide regular payments until death, and joint and survivor annuities, which pay less each month but continue to make payments to the spouse after the death of the retired worker. This article examines the payout decision and measures the share of married retirees with pension annuities who forego survivor protection. DESIGN AND METHODS: The analysis consists of a probit model of the pension payout decision, based on data from the 1992-2000 waves of the Health and Retirement Study. RESULTS: More than one quarter (28%) of married men and two thirds of married women receiving employer-sponsored retirement annuities declined survivor protection. Men with small pensions and limited household wealth, men in better health than their spouses, and men whose spouses have pension coverage from their own employers are more likely than other men to reject survivor protection. IMPLICATIONS: Most workers appear to make payout decisions by rationally balancing the costs and benefits of each type of annuity, suggesting that existing measures to encourage joint and survivor annuities are adequate. However, the growth in 401(k) plans, which are generally not covered by existing laws protecting spousal pension rights, may leave widows vulnerable.