Cost-effectiveness of screening for primary aldosteronism in hypertensive patients in Australia: a Markov modelling analysis.

BACKGROUND: Primary aldosteronism affects 3-14% of hypertensive patients in the primary care setting and up to 30% in the hypertensive referral units. Although primary aldosteronism screening is recommended in patients with treatment-resistant hypertension, diagnosis at an earlier stage of disease may prevent end-organ damage and optimize patient outcomes. METHODS: A Markov model was used to estimate the cost-effectiveness of screening for primary aldosteronism in treatment and disease (cardiovascular disease and stroke) naive hypertensive patients. Within the model, a 40-year-old patient with hypertension went through either the screened or the unscreened arm of the model. They were followed until age 80 or death. In the screening arm, the patient underwent standard diagnostic testing for primary aldosteronism if the screening test, aldosterone-to-renin ratio, was elevated above 70 pmol/l : mU/l. Diagnostic accuracies, transition probabilities and costs were derived from published literature and expert advice. The main outcome of interest was the incremental cost effectiveness ratio (ICER). RESULTS: Screening hypertensive patients for primary aldosteronism compared with not screening attained an ICER of AU$35 950.44 per quality-adjusted life year (QALY) gained. The results were robust to different sensitivity analyses. Probabilistic sensitivity analysis demonstrated that in 73% of the cases, it was cost-effective to screen at the commonly adopted willingness-to-pay (WTP) threshold of AU$50 000. CONCLUSION: The results from this study demonstrated that screening all hypertensive patients for primary aldosteronism from age 40 is cost-effective. The findings argue in favour of screening for primary aldosteronism before the development of severe hypertension in the Australian healthcare setting.

Differential mastery criteria impact sight word acquisition and maintenance: Application to individual operants and teaching trial doses.

We compared the effects of different "mastery" criteria and doses on the acquisition and maintenance of sight words for 4 second graders with and without disabilities. First, we replicated Set Analysis and Operant Analysis conditions where participants were taught sight words in 20-trial (4 operants, 5 opportunities) sessions. Acquisition criteria were applied to a set of 4 operants or to individual operants, respectively. Second, we extended the literature by evaluating a lower dose of the Operant Analysis condition in a 12-trial session (4 operants, 3 opportunities). Thus, we compared 3 conditions-Set Analysis 5, Operant Analysis 5, and Operant Analysis 3. All participants acquired novel sight words fastest and required far fewer teaching trials to maintain each sight word under Operant Analysis 3 compared with Set Analysis 5 and Operant Analysis 5 conditions. Implications for arranging acquisition criteria and the interaction with trial-dosages are discussed.

Units of analysis in acquisition-performance criteria for "mastery": A systematic replication.

This study compared 2 units of analysis for assessing acquisition mastery during sight word instruction for 3 participants. The unit of analysis refers to the specific performances that criteria are applied to, either sets of stimuli or individual operants. In the Set Analysis condition, we applied the acquisition-performance criterion to the aggregated accuracy of a set of 4 target operants. In the Operant Analysis (OA) condition, we assessed the criterion for individual operants and replaced targets as they met the acquisition criterion. All participants acquired novel textual responses to sight words faster under the OA condition and response maintenance was similar between conditions. This study extended previous research by showing enhanced response maintenance in the OA condition by increasing the performance criterion from 1 observation of 100% accuracy to 2. This study also suggests a unique contribution of OA to quickening learning.