Validation of algorithms to estimate gestational age at birth in the Medicaid Analytic eXtract-Quantifying the misclassification of maternal drug exposure during pregnancy.

PURPOSE: Accurate ascertainment of gestational age (GA) has been a challenge in perinatal epidemiologic research. To date, no study has validated GA algorithms in Medicaid Analytic eXtract (MAX). METHODS: We linked livebirths of mothers enrolled in Medicaid ≥30 days after delivery in 1999-2010 MAX to state birth certificates. We used clinical/obstetric estimate of gestation on the birth certificates as gold standard to validate claims-based GA algorithms. We calculated the proportions of deliveries with algorithm-estimated GA within 1-/2-weeks of the gold standard, the sensitivity, specificity, and positive/negative predictive value (PPV/NPV) of exposure to select medications during specific gestation windows, and quantified the impact of exposure misclassification on hypothetical relative risk (RR) estimates. RESULTS: We linked 1 336 495 eligible deliveries. Within 1-week agreement was 77%-80% overall and 47%-56% for preterm deliveries. The trimester-specific drug exposure status had high sensitivities and PPVs (88.5%-98.5%), and specificities and NPVs (>99.0%). Assuming a hypothetical RR of 2.0, bias associated with exposure misclassification during first trimester ranged from 10% to 40% under non-differential/differential misclassification assumptions. CONCLUSIONS: Claims-based GA algorithms had good agreement with the gold standard overall, but lower agreement among preterm deliveries, potentially resulting in biased risk estimated for pregnancy exposure evaluations.

Feasibility of short-term infusion of magnesium sulfate in pediatric patients with status asthmaticus.

OBJECTIVE: This report describes the feasibility of high-dose magnesium sulfate infusion in pediatric patients with status asthmaticus. METHODS: Retrospective chart review over a 3-year period of all patients younger than 18 years of age with status asthmaticus who underwent a high-dose magnesium sulfate infusion for 4 hours. All patients were breathing spontaneously but were refractory to conventional therapy. The magnesium sulfate infusion regimen was 50 mg/kg (for patients weighing >30 kg) or 75 mg/kg (for those weighing ≤30 kg) over a period of 30 to 45 minutes, followed by a continuous infusion of 40 mg/kg/hr for 4 hours. Information regarding vital and clinical respiratory signs, serum magnesium (SrMg), ionized magnesium (iMg), electrocardiograms, and cardiac troponin levels were retrieved. We analyzed the relationship between SrMg and iMg by using linear regression analysis. RESULTS: Nineteen patients were included. At the end of the infusion, SrMg levels were 4.4 ± 0.8 mg/dL, and iMg levels were 0.95 ± 0.2 mmol/L. SrMg levels only moderately predicted iMg (r(2) = 0.541). There were no reports of hypotension, respiratory failure, neurological problems, or nausea. Discomfort at the site of infusion was reported in three cases. Troponin levels (n = 12) and electrocardiograms (n = 12), when available, were noted at the end of the infusion and were normal in all patients p=0.01. CONCLUSIONS: In this case series, short-term high-dose administration of magnesium sulfate in the context of status asthmaticus was feasible, and we did not observe clinical complications with its use. Total SrMg was inadequate to reflect the active form of magnesium, iMg. The dose used achieved theoretical therapeutic levels of iMg.

Longitudinal study of optic cup progression in children.

PURPOSE: To determine the normative rate of cup-to-disc-ratio (C:D) progression in children and the effect of prematurity and low birth weight on this rate. METHOD: In a single pediatric ophthalmology practice, a single examiner evaluated optic cup size by serial ophthalmoscopy over a minimum of 5 years in 92 patients (184 eyes) without intraocular surgery or optic nerve disease. A cross-sectional analysis of C:D was performed per year of age from 0 to 10 years and linear regression was used to compare C:D progression between preterm and term children and between low versus normal birth weight children. RESULTS: Children exhibited progressive optic cupping. In term children, mean C:D increased by 0.0075 per year. Rate of mean C:D progression was double in children born preterm: 0.0160 (P = .049, comparison to term) per age-year. A similar, nonsignificant trend is observed when comparing low birth weight to normal children (P = .131). CONCLUSION: Prematurity and low birth weight are associated with increased rate of cupping in children. Clinicians should recognize that C:D progression is not a specific sign of glaucoma in children.

Cost-utility analysis of rimonabant in the treatment of obesity.

OBJECTIVE: To estimate the incremental cost-utility ratio (ICUR) of rimonabant 20 mg/day in the treatment of obesity from a third-party payer's perspective. METHODS: Pooled data from three randomized clinical trials were used to develop a decision tree with five treatment alternatives: 1- and 2-year treatment with rimonabant, 2-year placebo, 1-year rimonabant followed by 1-year placebo, and no treatment. All alternatives, except no treatment, were accompanied by lifestyle interventions. Treatment benefits included gains in quality-adjusted life-years (QALYs) and reduced incidence of type-2 diabetes mellitus and coronary heart disease (CHD). Drug acquisition cost was based on the average wholesale price of a comparator drug minus 15%. One-way and probabilistic sensitivity analyses were conducted to assess the stability of the base-case results. RESULTS: One-year rimonabant and 1-year rimonabant followed by placebo were extensively dominated. Rimonabant for 2 years showed an average weight reduction of 8.49 kg, a body mass index reduction of 2.98 kg/m(2) and reduced waist circumference by 8.24 cm (placebo: 3.55 kg, 1.22 kg/m(2), 4.18 cm). Two-year rimonabant was associated with a relative reduction in the 5-year incidence of CHD by 7.15% and of diabetes by 9.28%. Incremental benefits (costs) were 0.0984 QALYs ($5209) compared to no treatment and 0.0581 QALYs ($4182) compared to placebo, producing ICURs of $52,936/QALY (95% confidence interval $39K-$69K) and $71,973/QALY ($51K-$98K), respectively. CONCLUSIONS: Rimonabant combined with lifestyle interventions has the potential to decrease the rate of obesity-related comorbidities and improve health-related quality of life, albeit at considerable cost.