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The authors prospectively studied 455 consecutive patients referred to the general medical consultation service for cardiac risk assessment prior to non-cardiac surgery, in order to validate a previously derived multifactorial index in their clinical setting. They also tested a version of the index that they had modified to reflect factors they believed to be important. For patients undergoing major surgery, the original index performed less well in the validation data set than in the original derivation set (p less than 0.05), but still added predictive information to a statistically significant degree (p less than 0.05). The modified index also added predictive information for patients undergoing both major and minor surgery, demonstrating an area under the Receiver Operating Characteristic curve of 0.75 (95% confidence interval of 0.70 to 0.80). A simple nomogram is presented which will enable conversion of pretest probabilities into posttest probabilities using the likelihood ratios associated with each risk score. It is recommended that clinicians estimate local overall complication rates (pretest probabilities) for the clinically relevant populations in their settings before they apply the predictive properties (likelihood ratios) demonstrated in this study in order to calculate cardiac risks for individual patients (posttest probabilities). [ABSTRACT FROM AUTHOR]

Quality of life and quality-adjusted survival were measured for a cohort of 73 patients maintained on long-term parenteral nutrition at home (HPN) for periods ranging from six months to 12 years. Quality-adjusted survival was also modeled (although not directly observed) for this cohort under alternative therapeutic strategies (e.g., parenteral nutrition in hospital as needed). Using three utility assessment techniques (category scaling, time-tradeoff, direct questioning of objectives), quality of life was measured through interviews with 37 patients. The quality of life of the patients interviewed was good (mean value 0.73 where 0 represents death and 1.0 represents perfect health); for those who had experienced a period of chronic malnutrition before HPN, quality of life had improved. For the entire cohort, the estimate of quality-adjusted survival was four times greater with HPN than with the alternative therapeutic strategies (p less than 0.001). In comparison with alternative strategies, HPN significantly improves the quality of life of patients unable to sustain themselves with oral alimentation. Quality of life (utility) techniques can be used to evaluate the effectiveness of interventions for patients with chronic diseases. [ABSTRACT FROM AUTHOR]

An abstract of the article "Assessment of tinnitus: measurement of treatment outcomes," by M.B. Meikle and B.J. Stewart is presented.

Evidence exists that clinical outcomes improve for stroke patients admitted to specialized Stroke Units. The Toronto Western Hospital created a Neurovascular Unit (NVU) using beds from general internal medicine, Neurology and Neurosurgery to care for patients with stroke and acute neurovascular conditions. Using patient-level data for NVU-eligible patients, a discrete event simulation was created to study changes in patient flow and length of stay pre- and post-NVU implementation. Varying patient volumes and resources were tested to determine the ideal number of beds under various conditions. In the first year of operation, the NVU admitted 507 patients, over 66% of NVU-eligible patient volumes. With the introduction of the NVU, length of stay decreased by around 8%. Scenario testing showed that the current level of 20 beds is sufficient for accommodating the current demand and would continue to be sufficient with an increase in demand of up to 20%.

The value associated with self-perceived hearing aid benefit was assessed using a "willingness-to-pay" (WTP) approach. Abbreviated Profile of Hearing Aid Benefit (APHAB) data were obtained from 79 veterans who also indicated how much they were willing to pay for each hearing aid. The results of a multiple regression analysis revealed that veterans were willing to pay $22.06 more for a hearing aid for each 1-point increase in APHAB global benefit. A second multiple regression analysis revealed that the APHAB subscale scores for Ease of Communication (EC) benefit and understanding speech in Background Noise (BN) benefit, as well as income level, were all significant predictors of WTP. In addition, each 1-point increase in EC, BN, and Reverberation benefit increased the value associated with amplification by $16.32, $16.88, and $13.78, respectively. Each 1-point increase in the Aversiveness of Sounds subscale decreased the value associated with amplification by $7.63. The mean WTP across all income groups was $981.71 per hearing aid. These data are interpreted to support the use of WTP as a valid measure of hearing aid benefit.

In the absence of good clinical evidence from a randomized trial, the authors performed a decision analysis to determine the potential value of early elective surgery (OPNOW) for patients with left-sided Staphylococcus aureus infective endocarditis. Initial impressions (before performance of decision analysis) and initial runs at the formal models using probability estimates derived from clinicians suggested that OPNOW (i.e., within a few days of starting antibiotics) offered no advantage over attempted medical cure (WAIT) (life expectancy: WAIT = 325 weeks; OPNOW = 255 weeks). Extensive sensitivity analyses identified critical variables that needed further empirical estimation. The Manitoba Health Services Commission database identified 127 incident cases of endocarditis between April 1, 1979, and March 31, 1985, enabling estimation of values for these critical variables. With these estimates, the early surgery strategy appeared much better than the previous analyses had suggested (life expectancy: WAIT = 208 weeks, OPNOW = 256 weeks). The authors believe that this approach of combining decision analysis with medical claims databases is useful as an alternative or precursor to randomized trials, especially where the resource requirements and logistic difficulties of performing randomized trials are great.

In order to gain insight into the impact that decision analysis has had on clinical practice, we presented a published report on the utility of renal biopsy for patients with idiopathic nephrotic syndrome to a group of nephrologists and residents at a teaching hospital. Although the analysis showed that the decision to biopsy or use empiric steroids without biopsy was a toss-up in terms of patient outcomes, only one of six staff nephrologists was willing to forego the biopsy strategy. Many clinicians in the group discussed the pure value of the information (e.g in making statements about prognosis) derived from the biopsy as an important factor in the choice of clinical strategies, a characteristic which was not captured by the published analysis. Also, some clinicians were uncomfortable with the entire simulation process as there were no "real patients" in the study. It appeared that clinical intuition based on pattern recognition could not be influenced by the linear logic of decision analysis. We suggest that major challenges for decision analysts include incorporating the value of information into analyses, selecting and cultivating the most appropriate clinical audience, and demonstrating the benefits of decision analysis for either the decision-making process or health outcomes. Without meeting these challenges, decision analysis may remain an esoteric field within academic medicine, which will continue to have limited impact on clinical practice.

In this article, we describe a multifactorial cardiac risk index that can be used to assess patients undergoing noncardiac surgery. The index is a modified version of an index that was previously generated by Goldman and coworkers on a set of 1001 consecutive patients and prospectively validated in our clinical setting (a general medical consultation service in a large teaching hospital) on 455 patients. We present a Bayesian approach to assessing cardiac risks by converting average risks for patients undergoing particular surgical procedures (pretest probabilities) to average risks for patients with each index score (posttest probabilities). A simple nomogram is presented for performing such a calculation.

Quality of life and quality-adjusted survival were measured for a cohort of 73 patients maintained on long-term parenteral nutrition at home (HPN) for periods ranging from six months to 12 years. Quality-adjusted survival was also modeled (although not directly observed) for this cohort under alternative therapeutic strategies (e.g., parenteral nutrition in hospital as needed). Using three utility assessment techniques (category scaling, time-tradeoff, direct questioning of objectives), quality of life was measured through interviews with 37 patients. The quality of life of the patients interviewed was good (mean value 0.73 where 0 represents death and 1.0 represents perfect health); for those who had experienced a period of chronic malnutrition before HPN, quality of life had improved. For the entire cohort, the estimate of quality-adjusted survival was four times greater with HPN than with the alternative therapeutic strategies (p less than 0.001). In comparison with alternative strategies, HPN significantly improves the quality of life of patients unable to sustain themselves with oral alimentation. Quality of life (utility) techniques can be used to evaluate the effectiveness of interventions for patients with chronic diseases.

The authors prospectively studied 455 consecutive patients referred to the general medical consultation service for cardiac risk assessment prior to non-cardiac surgery, in order to validate a previously derived multifactorial index in their clinical setting. They also tested a version of the index that they had modified to reflect factors they believed to be important. For patients undergoing major surgery, the original index performed less well in the validation data set than in the original derivation set (p less than 0.05), but still added predictive information to a statistically significant degree (p less than 0.05). The modified index also added predictive information for patients undergoing both major and minor surgery, demonstrating an area under the Receiver Operating Characteristic curve of 0.75 (95% confidence interval of 0.70 to 0.80). A simple nomogram is presented which will enable conversion of pretest probabilities into posttest probabilities using the likelihood ratios associated with each risk score. It is recommended that clinicians estimate local overall complication rates (pretest probabilities) for the clinically relevant populations in their settings before they apply the predictive properties (likelihood ratios) demonstrated in this study in order to calculate cardiac risks for individual patients (posttest probabilities).