Risk Factors for Pediatric Asthma Readmissions: A Systematic Review.

OBJECTIVE: To systematically review the literature on pediatric asthma readmission risk factors. STUDY DESIGN: We searched PubMed/MEDLINE, CINAHL, Scopus, PsycINFO, and Cochrane Central Register of Controlled Trials for published articles (through November 2019) on pediatric asthma readmission risk factors. Two authors independently screened titles and abstracts and consensus was reached on disagreements. Full-text articles were reviewed and inclusion criteria applied. For articles meeting inclusion criteria, authors abstracted data on study design, patient characteristics, and outcomes, and 4 authors assessed bias risk. RESULTS: Of 5749 abstracts, 74 met inclusion criteria. Study designs, patient populations, and outcome measures were highly heterogeneous. Risk factors consistently associated with early readmissions (≤30 days) included prolonged length of stay (OR range, 1.1-1.6) and chronic comorbidities (1.7-3.2). Risk factors associated with late readmissions (>30 days) included female sex (1.1-1.6), chronic comorbidities (1.5-2), summer discharge (1.5-1.8), and prolonged length of stay (1.04-1.7). Across both readmission intervals, prior asthma admission was the most consistent readmission predictor (1.3-5.4). CONCLUSIONS: Pediatric asthma readmission risk factors depend on the readmission interval chosen. Prior hospitalization, length of stay, sex, and chronic comorbidities were consistently associated with both early and late readmissions. TRIAL REGISTRATION: CRD42018107601.

Deletion of Rac in Mature Osteoclasts Causes Osteopetrosis, an Age-Dependent Change in Osteoclast Number, and a Reduced Number of Osteoblasts In Vivo.

Rac1 and Rac2 are thought to have important roles in osteoclasts. Therefore, mice with deletion of both Rac1 and Rac2 in mature osteoclasts (DKO) were generated by crossing Rac1(flox/flox) mice with mice expressing Cre in the cathepsin K locus and then mating these animals with Rac2(-/-) mice. DKO mice had markedly impaired tooth eruption. Bone mineral density (BMD) was increased 21% to 33% in 4- to 6-week-old DKO mice at all sites when measured by dual-energy X-ray absorptiometry (DXA) and serum cross-linked C-telopeptide (CTx) was reduced by 52%. The amount of metaphyseal trabecular bone was markedly increased in DKO mice, but the cortices were very thin. Spinal trabecular bone mass was increased. Histomorphometry revealed significant reductions in both osteoclast and osteoblast number and function in 4- to 6-week-old DKO animals. In 14- to 16-week-old animals, osteoclast number was increased, although bone density was further increased. DKO osteoclasts had severely impaired actin ring formation, an impaired ability to generate acid, and reduced resorptive activity in vitro. In addition, their life span ex vivo was reduced. DKO osteoblasts expressed normal differentiation markers except for the expression of osterix, which was reduced. The DKO osteoblasts mineralized normally in vitro, indicating that the in vivo defect in osteoblast function was not cell autonomous. Confocal imaging demonstrated focal disruption of the osteocytic dendritic network in DKO cortical bone. Despite these changes, DKO animals had a normal response to treatment with once-daily parathyroid hormone (PTH). We conclude that Rac1 and Rac2 have critical roles in skeletal metabolism.