Epidemiology of myasthenia gravis in the United States.

Introduction: Global studies of epidemiology of myasthenia gravis (MG) have pointed to increasing prevalence of this rare autoimmune disorder affecting the neuromuscular synapse; however, no new data for the USA were available for decades. We aimed to estimate the incidence rate and prevalence of MG in a large-scale insured US population. Methods: We conducted a population-based retrospective cohort study to estimate the annual incidence and prevalence of MG cases in the USA during 2017. Using a previously validated algorithm, we identified cases of MG in two Truven Health MarketScan databases, which during 2017 included a sample of approximately 20 million commercially insured and Medicare recipients, plus 10 million Medicaid recipients. We report crude incidence and prevalence and calculated age-and sex-standardized estimates for the USA based on the 2017 American Community Survey. We estimated the number of adult cases during 2021 by extrapolating from the stratified estimates to the population size from the 2021 American Community Survey. Results: From the US commercially/Medicare-insured cohort, we calculated an age-and sex-standardized incidence of 68.5 new cases per million person-years with an adjusted prevalence of 316.4 per million. Within the Medicaid-insured population, similar yet slightly lower numbers emerged: the adjusted incidence was 49.7 new cases per million person-years, and the adjusted prevalence rate was 203.7 cases per million. Given our results, we were able to estimate that there were approximately 82,715 US adults living with MG in 2021 (or an estimated 320.2 cases per million adults in the USA). We observed a strong effect of age and sex when stratifying the identified incidence rate and prevalence, with a pattern of female preponderance among the younger age brackets, a male preponderance for older cases in the commercially/Medicare-insured cohort, and the disease incidence and prevalence steadily increasing with age. Discussion: Our updated US population-based estimates of MG epidemiology demonstrate an increase in the previously reported incidence and prevalence from over 20 years ago, in keeping with developments in westernized, industrialized countries. Notable findings of steadily increasing prevalence with age, driven by robust increases in elderly males, prompts questions for basic-translational research, therapeutics, and public health.

Validation of mother-infant linkage using Medicaid Case ID variable within the Medicaid Analytic eXtract (MAX) database.

PURPOSE: The state-assigned Case ID number in the Medicaid Analytic eXtract (MAX) allows for potential linkage of mothers to infants. No validation of respective linkage algorithms is available. We established and validated an algorithm within MAX that links mothers to infants and to identify factors influencing successful mother-infant linkage. METHODS: We identified all mother-infant pairs in FL and TX birth certificates records (BCR) that could be linked individually to MAX records (1999-2005 for FL and 1999-2010 for TX) based on Social Security Number (gold standard pairs). Case ID linkage performance was evaluated as the proportion of gold standard mother-infant pairs that were identified by the algorithm (sensitivity) and the proportion of algorithm defined mother-infant pairs that were correctly linked. Generalized estimating equations were used to calculate the probability for successful Case ID algorithm linkage versus non-linkage using maternal and infant characteristics. RESULTS: We identified 323,160 gold standard pairs in FL BCR and MAX and 1,025,350 in TX BCR and MAX. Depending on Medicaid enrollment the algorithm sensitivity ranged from 85.51% to 87.96% in FL and 19.60% to 35.75% in TX. In both states, positive predictive value exceeded 99%, regardless of enrollment periods. Determinants for successful linkage varied across states, but suggested better results for younger mothers, minority women, and those with lower educational achievement. CONCLUSIONS: Our algorithm can correctly link liveborn infants to their mothers. The algorithm's sensitivity in identifying pairs varied across states, but PPV was consistently high. Linkage performance was associated with certain characteristics that may affect representativeness of successfully linked pairs.

Anti-diabetic drug utilization of pregnant diabetic women in us managed care.

BACKGROUND: With the increasing prevalence of type 2 diabetes in young adulthood, treatment of diabetes in pregnancy faces new challenges. Anti-diabetic drug utilization patterns of pregnant women with pre-existing diabetes are poorly described. We aim to describe anti-diabetic (AD) agent utilization among diabetic pregnant women. METHODS: We utilized IMS LifeLink, including administrative claims data of patients in US managed care plans, to establish a retrospective cohort of women, age 18-46 years (N = 96,740) with billed procedures for a live birth, and a 12 month eligibility period before and 3 month after delivery. Diabetes mellitus was identified from ≥2 in- or outpatient claims with diagnoses (ICD-9-CM 250.XX) before pregnancy. We estimated the prevalence of AD drugs before, during and after pregnancy, and secular trends across the study period (1999-2009), using linear regression. A sensitivity analysis was conducted to identify the extent of misclassification of trimesters. RESULTS: Almost six percent (n = 5,581) of the live birth cohort had diabetes mellitus. Throughout the study, 48% (1999) and 78% (2009) (p < 0.0001) of diabetic women received AD drugs during pregnancy. The most common AD drugs during pregnancy were insulin, metformin, sulfonylureas, thiazolidinediones (TZD), and combination AD. The annual prevalence of insulin use increased by only 1% from 39% (1999) to 40% (2009) (p = 0.589) during pregnancy, while use of sulfonylureas and metformin increased from 2.5% and 4.2% (1999) to 17.3% and 15.3% (2009) (p < 0.0001), respectively. Insulin and sulfonylurea use steadily increased in prevalence from the 1st to 3rd trimester (16.5% and 3.3% to 33.0% and 7.5%), while metformin and TZD use decreased (11.4% and 1.6% to 3.8% and 0.2%). CONCLUSIONS: AD use during pregnancy demonstrates the need for additional investigation regarding safety and efficacy of AD drugs on maternal outcomes.

Appropriateness of age thresholds for respiratory syncytial virus immunoprophylaxis in moderate-preterm infants: a cohort study.

IMPORTANCE Recommendations concerning the appropriate age threshold for respiratory syncytial virus (RSV) prophylaxis in moderate-preterm infants are highly debated. OBJECTIVE To determine the age at which moderate-preterm infants' risk of RSV hospitalization has decreased to the risk observed in low-risk term infants. DESIGN, SETTING, AND PARTICIPANTS Retrospective cohort study of Florida and Texas Medicaid fee-for-service billing records matched to birth certificates from Medicaid beneficiaries aged 0 to 12 months with a sibling younger than 5 years and without other indications for RSV prophylaxis between January 1, 1999, and December 31, 2004. EXPOSURES For each state, we used discrete time survival analysis to develop age trend models for RSV hospitalizations for 2 groups: moderate-preterm infants (32-34 weeks' gestational age) and term infants (37-41 weeks' gestational age). MAIN OUTCOMES AND MEASURES Age at which preterm infants' risk of RSV hospitalization equaled the risk for term infants at age 1 month. RESULTS Our cohort included 247,566 eligible infants with 5322 RSV hospitalizations. Preterm status doubled the risk for RSV hospitalization in both Florida (odds ratio = 2.41; 95% CI, 1.85-3.12) and Texas (odds ratio = 1.94; 95% CI, 1.64-2.30). Preterm infants' risk of RSV hospitalization was similar to that for 1-month-old term infants at ages 4.2 months (95% CI, 2.5-5.7) in Florida and 4.5 months (95% CI, 2.8-6.4) in Texas. CONCLUSIONS AND RELEVANCE The age at which moderate-preterm infants showed RSV hospitalization risk similar to their healthy term counterparts supports the more restrictive age thresholds in RSV immunoprophylaxis recommendations. Further studies are warranted to investigate the age-dependent risk of RSV hospitalization in other RSV risk groups.

Evaluating promotional claims as false or misleading.

In light of the "false or misleading" standard resulting from the recent legal ruling, it can be concluded that a true claim is one that is both factually and analytically true. Factual truth could be based on the accuracy of the information and the sufficiency of the information. Analytical truth could be based on the scientific foundation for the claim and whether the information within the claim is presented in a balanced way. Regarding the assessment of whether a truthful claim is misleading, the evaluator could consider the relevance, consistency, and context of the information. Standards are important in medication use and medication regulation. Health care professionals who must decide whether a claim is truthful and not misleading will rely on guidance from FDA in determining how to evaluate promotional claims. As the court suggested in the case reviewed here, FDA could take the lead and provide guidance "in differentiating between misleading and false promotion, exaggerations and embellishments, and truthful or non-misleading information." Existing FDA regulations provide a foundation for such guidance. The next step for the agency would be to expand existing guidance to specifically describe how an off-label claim can be identified as either false or misleading.