Association of Insurance Type With Inpatient Surgery 30-Day Complications and Costs.

INTRODUCTION: Safety-net hospitals (SNHs) have higher postoperative complications and costs versus low-burden hospitals. Do low socioeconomic status/vulnerable patients receive care at lower-quality hospitals or are there factors beyond providers' control? We studied the association of private, Medicare, and vulnerable insurance type with complications/costs in a high-burden SNH. METHODS: Retrospective inpatient cohort study using National Surgical Quality Improvement Program (NSQIP) data (2013-2019) with cost data risk-adjusted by frailty, preoperative serious acute conditions (PASC), case status, and expanded operative stress score (OSS) to evaluate 30-day unplanned reoperations, any complication, Clavien-Dindo IV (CDIV) complications, and hospitalization variable costs. RESULTS: Cases (Private 1517; Medicare 1224; Vulnerable 3648) with patient mean age 52.3 y [standard deviation = 14.7] and 47.3% male. Adjusting for frailty and OSS, vulnerable patients had higher odds of PASC (aOR = 1.71, CI = 1.39-2.10, P < 0.001) versus private. Adjusting for frailty, PASC and OSS, Medicare (aOR = 1.27, CI = 1.06-1.53, P = 0.009), and vulnerable (aOR = 2.44, CI = 2.13-2.79, P < 0.001) patients were more likely to undergo urgent/emergent surgeries. Vulnerable patients had increased odds of reoperation and any complications versus private. Variable cost percentage change was similar between private and vulnerable after adjusting for case status. Urgent/emergent case status increased percentage change costs by 32.31%. We simulated "switching" numbers of private (3648) versus vulnerable (1517) cases resulting in an estimated variable cost of $49.275 million, a 25.2% decrease from the original $65.859 million. CONCLUSIONS: Increased presentation acuity (PASC and urgent/emergent surgeries) in vulnerable patients drive increased odds of complications and costs versus private, suggesting factors beyond providers' control. The greatest impact on outcomes may be from decreasing the incidence of urgent/emergent surgeries by improving access to care.

Altered macrophage phenotype transition impairs skeletal muscle regeneration.

Monocyte/macrophage polarization in skeletal muscle regeneration is ill defined. We used CD11b-diphtheria toxin receptor transgenic mice to transiently deplete monocytes/macrophages at multiple stages before and after muscle injury induced by cardiotoxin. Fat accumulation within regenerated muscle was maximal when ablation occurred at the same time as cardiotoxin-induced injury. Early ablation (day 1 after cardiotoxin) resulted in the smallest regenerated myofiber size together with increased residual necrotic myofibers and fat accumulation. However, muscle regeneration after late (day 4) ablation was similar to controls. Levels of inflammatory cells in injured muscle following early ablation and associated with impaired muscle regeneration were determined by flow cytometry. Delayed, but exaggerated, monocyte [CD11b(+)(CD90/B220/CD49b/NK1.1/Ly6G)(-)(F4/80/I-Ab/CD11c)(-)Ly6C(+/-)] accumulation occurred; interestingly, Ly6C(+) and Ly6C(-) monocytes were present concurrently in ablated animals and control mice. In addition to monocytes, proinflammatory, Ly6C(+) macrophage accumulation following early ablation was delayed compared to controls. In both groups, CD11b(+)F4/80(+) cells exhibited minimal expression of the M2 markers CD206 and CD301. Nevertheless, early ablation delayed and decreased the transient accumulation of CD11b(+)F4/80(+)Ly6C(-)CD301(-) macrophages; in control animals, the later tissue accumulation of these cells appeared to correspond to that of anti-inflammatory macrophages, determined by cytokine production and arginase activity. In summary, impairments in muscle regeneration were associated with exaggerated monocyte recruitment and reduced Ly6C(-) macrophages; the switch of macrophage/monocyte subsets is critical to muscle regeneration.

Increased fat deposition in injured skeletal muscle is regulated by sex-specific hormones.

Sex differences in skeletal muscle regeneration are controversial; comparisons of regenerative events between sexes have not been rigorously defined in severe injury models. We comprehensively quantified inflammation and muscle regeneration between sexes and manipulated sex-specific hormones to determine effects on regeneration. Cardiotoxin injury was induced in intact, castrated and ovariectomized female and male mice; ovariectomized mice were replaced with low- or high-dose 17-ß estradiol (E(2)) or progesterone (P4). Extent of injury was comparable between intact mice, but females were more efficient in removal of necrotic debris, despite similar tissue levels of inflammatory cells and chemokines. Myofiber size during regeneration was equivalent between intact mice and after castration or ovariectomy (OVX) but was decreased (P < 0.001) in ovariectomized mice with high-dose E(2) replacement. Intermuscular adipocytes were absent in uninjured muscle, whereas adipocyte area was increased among regenerated myofibers in all groups. Interestingly, intermuscular fat was greater (P = 0.03) in intact females at day 14 compared with intact males. Furthermore, castration increased (P = 0.01) and OVX decreased adipocyte accumulation. After OVX, E(2), but not P4, replacement decreased (P ≤ 0.03) fat accumulation. In conclusion, sex-dependent differences in regeneration consisted of more efficient removal of necrosis and increased fat deposition in females with similar injury, inflammation, and regenerated myofiber size; high-dose E(2) decreased myofiber size and fat deposition. Adipocyte accumulation in regenerating muscle was influenced by sex-specific hormones. Recovery following muscle injury was different between males and females, and sex-specific hormones contributed to these differences, suggesting that sex-specific treatments could be beneficial after injury.

Association of Socioeconomic Area Deprivation Index with Hospital Readmissions After Colon and Rectal Surgery.

BACKGROUND: Risk adjustment for reimbursement and quality measures omits social risk factors despite adversely affecting health outcomes. Social risk factors are not usually available in electronic health records (EHR) or administrative data. Socioeconomic status can be assessed by using US Census data. Distressed Communities Index (DCI) is based upon zip codes, and the Area Deprivation Index (ADI) provides more granular estimates at the block group level. We examined the association of neighborhood disadvantage using the ADI, DCI, and patient-level insurance status on 30-day readmission risk after colorectal surgery. METHODS: Our 677 patient cohort was derived from the 2013-2017 National Surgical Quality Improvement Program at a safety net hospital augmented with EHR data to determine insurance status and 30-day readmissions. Patients' home addresses were linked to the ADI and DCI. RESULTS: Our cohort consisted of 53.9% males and 63.8% Hispanics with a 22.9% 30-day readmission rate from the date of discharge; > 50% lived in highly deprived neighborhoods. Controlling for medical comorbidities and complications, ADI was associated with increased risk of 30 days from the date of discharge readmissions among patients living in medium (OR = 2.15, p = .02) or high (OR = 1.88, p = .03) deprived areas compared to less-deprived neighborhoods, but not insurance status or DCI. CONCLUSIONS: The ADI identified patients living in deprived communities with increased readmission risk. Our results show that block-group level ADI can potentially be used in risk adjustment, to identify high-risk patients and to design better care pathways that improve health outcomes.

Increased Adipocyte Area in Injured Muscle With Aging and Impaired Remodeling in Female Mice.

We demonstrated that young male and female mice similarly regenerated injured skeletal muscle; however, female mice transiently increased adipocyte area within regenerated muscle in a sex hormone-dependent manner. We extended these observations to investigate the effect of aging and sex on sarcopenia and muscle regeneration. Cardiotoxin injury to the tibialis anterior muscle of young, middle, and old-aged C57Bl/6J male and female mice was used to measure regenerated myofiber cross-sectional area (CSA), adipocyte area, residual necrosis, and inflammatory cell recruitment. Baseline (uninjured) myofiber CSA was decreased in old mice of both sexes compared to young and middle-aged mice. Regenerated CSA was similar in male mice in all age groups until baseline CSA was attained but decreased in middle and old age female mice compared to young females. Furthermore, adipocyte area within regenerated muscle was transiently increased in young females compared to young males and these sex-dependent increases persisted in middle and old age female mice and were associated with increased Pparg Young female mice had more pro-inflammatory monocytes/macrophages in regenerating muscle than young male mice and increased Sca-1(+)CD45(-)cells. In conclusion, sex and age influence pro-inflammatory cell recruitment, muscle regeneration, and adipocyte area following skeletal muscle injury.