Distribution of acute appendicitis care in children: A statewide assessment of the surgeons and facilities providing surgical care.

BACKGROUND: Pediatric appendicitis is managed by general and pediatric surgeons at both children's hospitals and non-children's hospitals. A statewide assessment of surgeons and facilities providing appendicitis care was performed to identify factors associated with location of surgical care. METHODS: Children aged <18 years undergoing appendectomy for appendicitis in Wisconsin from 2018-2020 were identified through the International Classification of Diseases, 10th revision, and Current Procedural Terminology codes using Wisconsin Hospital Association data. Patient residence and hospital locations were used to determine travel distance, rurality, and neighborhood-level socioeconomic status. RESULTS: Among 3,604 children with appendicitis, 36.0% and 12.8% had an appendectomy at 2 major children's hospitals and 4 other children's hospitals, respectively, and 51.2% had an appendectomy at 99 non-children's hospitals. Pediatric surgeons performed 76.1% of appendectomies at children's hospitals and 2.9% at non-children's hospitals. Only 32.2% of patients received care at the hospital closest to their homes. Non-children's hospitals disproportionally cared for older, non-Hispanic White, and privately insured children, those with uncomplicated appendicitis, and those living in rural areas, in mid-socioeconomic status neighborhoods, and greater distances from children's hospitals (all P < .001). After multivariable adjustment, receipt of care at children's hospitals was associated with younger age, minority race, complicated appendicitis, shorter distance to children's hospitals, and urban residence. CONCLUSION: Over half of surgical care for pediatric appendicitis occurred at non-children's hospitals, especially among older children and those living in rural areas far from children's hospitals. Future work is necessary to determine which children benefit most from care at children's hospitals and which can safely receive care at non-children's hospitals to avoid unnecessary time and resource utilization associated with travel to children's hospitals.

The Decay of Disease Association with Declining Linkage Disequilibrium: A Fine Mapping Theorem.

Several important and fundamental aspects of disease genetics models have yet to be described. One such property is the relationship of disease association statistics at a marker site closely linked to a disease causing site. A complete description of this two-locus system is of particular importance to experimental efforts to fine map association signals for complex diseases. Here, we present a simple relationship between disease association statistics and the decline of linkage disequilibrium from a causal site. Specifically, the ratio of Chi-square disease association statistics at a marker site and causal site is equivalent to the standard measure of pairwise linkage disequilibrium, r2. A complete derivation of this relationship from a general disease model is shown. Quite interestingly, this relationship holds across all modes of inheritance. Extensive Monte Carlo simulations using a disease genetics model applied to chromosomes subjected to a standard model of recombination are employed to better understand the variation around this fine mapping theorem due to sampling effects. We also use this relationship to provide a framework for estimating properties of a non-interrogated causal site using data at closely linked markers. Lastly, we apply this way of examining association data from high-density genotyping in a large, publicly-available data set investigating extreme BMI. We anticipate that understanding the patterns of disease association decay with declining linkage disequilibrium from a causal site will enable more powerful fine mapping methods and provide new avenues for identifying causal sites/genes from fine-mapping studies.