The Impact of Comorbid Health Conditions on Survival in Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia (CLL) tends to be diagnosed later in life; half of all patients with CLL are >70 years of age.¹ Although most patients respond to treatment, their odds of survival may be complicated by other health conditions that are present in elderly patients.¹ Indeed, for other cancers, it has been shown that having a greater number of concurrent health conditions, also called comorbidities, is associated with an increased risk of death.¹

In a recent study, researchers sought to understand how many patients with CLL have comorbidities, and what effect these comorbidities have on patient survival.¹ Using a registry of cancer patients in Girona, Spain, the researchers extracted data from the medical records of 400 patients with CLL or small lymphocytic lymphoma from 2008 to 2016.¹ Data included the patients’ Rai stage, which indicates the severity of CLL, and more than a dozen potential comorbidities that included heart disease, diabetes, other tumors, and AIDS status.¹

Based on the presence of comorbidities, the study investigators then calculated a value called the Charlson comorbidity index (CCI) for each patient.¹ The CCI is a way to rank patients with chronic illnesses into 1 of 5 groups based on their risk of death due to comorbidities.¹

Half of the patients in this study were >72 years of age when they were first diagnosed with CLL, and most patients (57%) had early-stage CLL (Rai stage 0).¹ Nearly all of the patients (99.5%) had at least 1 comorbid condition at diagnosis, most commonly diabetes (21% of patients) or congestive heart failure (18%).¹ Patients with more comorbidities (those with higher CCI scores) tended to be older and to be diagnosed with more advanced Rai stages.¹

Unsurprisingly, when looking at patient survival, those with the greater number of comorbidities when they were diagnosed had a greater risk of death at both the 3- and 5-year timepoints that were evaluated.¹ Whereas more than 95% of patients with a low CCI of 1 or 2 were likely to survive 5 years after their initial diagnosis, <50% of patients with a CCI score of ≥4 were expected to do the same.¹

As noted above, having a higher CCI score was also associated with being older and having more advanced CLL—2 factors that could increase a patient’s risk of dying.¹ Therefore, the investigators performed a more detailed statistical analysis to determine whether the decreased survival rate seen in this study could be explained by increased comorbidities alone. After performing this analysis, they concluded that a higher CCI score was not predictive of an increased mortality rate, and that age and CLL stage at diagnosis are likely more important predictors of survival than comorbidities alone.¹

Although this study showed a suggestive link between comorbidities at diagnosis and patient survival, further research is needed to explore the impact of comorbidities on CLL outcomes to provide care that is tailored to each patient’s needs.¹

Reference

1. Villavicencio A, Solans M, Zacarías-Pons L, et al. Comorbidities at diagnosis, survival, and cause of death in patients with chronic lymphocytic leukemia: a population-based study. Int J Environ Res Public Health. 2021;18:701.