In-hospital outcomes of hyponatremia in non-Hodgkin lymphoma patients: Insights from a 7-year national cohort study

Abstract

Abstract Background: Non-Hodgkin lymphoma (NHL) is one of the most common hematological malignancies in the United States with the mortality rate being the sixth highest in cancer related mortality. The outcomes are influenced by demographic and clinical factors. Hyponatremia, a common electrolyte abnormality, is associated with substantial morbidity and mortality in some cancers but has not been well studied in NHL. Currently, there is limited data regarding the risk hyponatremia confers on hospitalization outcomes in patients admitted with NHL and investigating this is essential for better outcomes and guiding public health policy. Our aim was to assess the impact of hyponatremia on clinical outcomes among patients with NHL. Methods: A retrospective study using NIS database (2016-22) was conducted. Adult patients admitted with diagnosis of NHL were identified and stratified based on the presence of hyponatremia. Covariates including demographic variables (age, sex, race), socioeconomic indicators (median income quartile, primary payer), hospital characteristics (region, teaching status, bed size), and comorbidity burden measured using the Charlson Comorbidity Index, categorized into three groups (0–3, 4–6, ≥7), were included in the base-line analyses. Outcomes studied included in-hospital mortality, length of stay (LOS), and total hospitalization charges. Survey-adjusted multivariate logistic regression was used for binary outcomes (e.g., mortality), while linear regression was used for continuous outcomes (e.g., LOS, total charges). Temporal trends were assessed over the study period using mean annual percent change (MAPC). Results were reported as adjusted odds ratios (aOR) or adjusted mean differences with 95% confidence intervals (CI). A p-value <0.05 was considered statistically significant. All of the analyses were performed using StataMP version 17. Results: Out of 260,210 hospitalizations for NHL, 14% patients had hyponatremia. 70 years and older patients (42% vs 38%; p<0.001) and Medicare insurance group (56% vs 51%; p<0.001) have more percentage of hyponatremic patients. Hyponatremic patients had more chronic health issues. 13% have Charlson Comorbidity Index (CCI) ≥7 (p<0.001). Mortality in hospital was higher for the hyponatremic patients (OR: 2.04 [1.85-2.24]; p<0.001). LOS was significantly longer for them (β=4.13 [3.73-4.52]; p<0.001) and their total charges were more ($57421 [48380-66462]; p<0.001) as compared to non hyponatremic patients. They were also less likely to be discharged to home. Over the seven years (2016-22) more NHL patients have presented with hyponatremia and the prevalence increased from 10.9% to 17.2% with MAPC of 6.8% (p=0.00001). Conclusion: This study shows that hyponatremia in patients with NHL is associated with greater baseline comorbidity burden, higher mortality, increased LOS and increased resource utilization. With time more NHL patients are presenting with hyponatremia. To reduce the adverse events in this population early recognition and improvement in management is recommended. Further research is needed to understand the underlying mechanism and support these observations.