DLBCL: The Impact of Socioeconomic Status on Outcomes
—Using information from a nationwide database, investigators in Germany set out to examine the effects of socioeconomic status on 5-year survival outcomes in patients with diffuse large B-cell lymphoma. Here’s what they found.
The International Prognostic Index (IPI) is currently used to assess risk and treatment options for patients with diffuse large B-cell lymphoma (DLBCL). However, according to the investigators of a newly published longitudinal study on the impact of socioeconomic status (SES) on outcomes in patients with DLBCL, the IPI doesn’t incorporate socioeconomic factors into its assessment. The IPI evaluates only clinical parameters that include the patient’s age, performance status, disease stage, lactate dehydrogenase levels, and extranodal site involvement.1
Based on an IPI-centered risk assessment, standard first-line therapies typically combine immunotherapeutic agents—a CD20-directed monoclonal antibody with or without a CD79b-directed antibody-drug conjugate—with conventional anthracycline-based chemotherapy. While the specific causal effects remain unclear, new research provides evidence of an independent relationship between nonbiologic factors, such as SES, and patient outcomes. The investigators behind the current analysis note that there are several hypotheses for this correlation, including disparities in healthcare access and insurance coverage, treatment quality, employment status, and comorbidity burden.
Measuring the impact of SES on survival
In an observational analysis, Ghandili and colleagues identified 49,465 patients (median age 70 years; 46.2% male) diagnosed with DLBCL between 2004 and 2019 from a nationwide German cancer registry.1 The study was designed to measure the potential impact of regional SES inequalities on 5-year overall survival (OS). Death within 5 years after a diagnosis of DLBCL was the primary outcome of the study.
Patients were followed until date of death, end of the study period, or 1827 days (5 years), whichever came first (median follow-up 3.64 years). The investigators compared patients with low SES (fifth quintile of the German Index of Socioeconomic Deprivation; n=9535) to those with middle SES (second to fourth quintile; n=28,389) and high SES (first quintile; n=11,541), based on the areas patients were living in. Nine SES indicators, which included education, employment, and income, were utilized.
Low SES puts patients at a disadvantage
Here’s what the investigators discovered. Death within 5 years of a DLBCL diagnosis occurred in approximately 34% of patients in this cohort (n=16,680). To put this in context, the background average probability of death within 1 year was 1.63%, and regional average premature mortality was 2.8 deaths per 1000 persons.
The investigators found significantly impaired 5-year OS among patients with DLBCL in low SES regions (59.2%) compared to those in middle and high SES areas (61.8% and 64.1%, respectively; P<.0001). However, when premature mortality in each region was accounted for in the analysis, no additional impact of SES on DLBCL outcomes was observed (hazard ratio 0.94, 95% confidence interval 0.87 to 1.01).
The investigators determined that higher comorbidity burden was the main driver of lower survival rates in patients living in low SES areas, rather than differences in diagnosis or treatment of DLBCL. Patients in low SES regions had a slightly higher share of males (47.8%) compared to patients in high SES regions (46.3%). Those in low SES versus high SES regions were also more likely to report earlier primary tumors (16.2% versus 12.3%) and less likely to live in a region with a certified hospital center (35.1% versus 39.9%). Premature mortality was also higher in the low versus high SES areas (3.43 versus 2.36 deaths per 1000 persons).
Limitations and conclusions
Limitations of the study include its reliance on cancer registry data that didn’t include prognostic variables, such as economic status, Ann Arbor stage or IPI, hospital volume and certification, treatment information, lifestyle and comorbidities, and education level. The study was limited by a lack of data on cancer progression or cause of death and, therefore, included only the single endpoint of all-cause mortality. It was also necessary to exclude 15% of the initial sample sizes, which lacked more-detailed information beyond a death certificate, such as data on the impact of SES, acute conditions, and frailty on short-term survival in patients with DLBCL.
“Further studies based on more-detailed data at the patient level should aim at verifying our central hypothesis that existing SES differentials among DLBCL patients are explained by factors not related to the diagnosis and treatment of the disease itself but rather by other coexisting risk factors and diseases,” the authors wrote. “However, from a nationwide perspective, even though a comprehensive health insurance setting exists, socioeconomic deprivation is related to a higher comorbidity burden and is translating into significant survival differences.”1
The authors suggest that there may be a need to pay more attention to the risks of comorbidities in patients with DLBCL based on SES.
“Although SES is not a prognostic factor for survival in DLBCL patients, medical guidelines may emphasize the need for tailoring treatment to the specific vulnerability caused by comorbidities in patients with socioeconomic deprivation,” they concluded.1
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