Little US comparative data exists on the incidence of CRBSIs in HPN patients with a cancer diagnosis who are actively undergoing oncologic treatments. In this study, we evaluated the incidence of CRBSI and the factors associated with it in cancer patients undergoing HPN at a tertiary care cancer center in the US.
We found an overall CRBSI incidence of 0.54 per 1000 HPN days following a standardized catheter care protocol. Several studies have evaluated the incidence of CRBSI in cancer patients receiving HPN. A prospective study by Cotogni et al. evaluated 269 PICCs in 250 cancer patients for a total of 55,293 catheter days, and found a CRBSI rate of 0.05 per 1000 catheter days. Seventy-one percent patients received chemotherapy during the study period . Another prospective study by the same research group, found a CRBSI rate of 0.35 per 1000 catheter days and 0.60 per 1000 HPN days . Other studies have reported CRBSI rates ranging from 0.41 to 1.7 per 1000 catheter days [21, 22, 24, 25, 30]. We did not find any significant difference in the incidence of CRBSI across the three types of VAD, though it is to be noted that of a total of 408 VADs in this study, only 11 (2.7%) were TCCs. This finding could also possibly suggest that the incidence of CRBSI in patients receiving HPN might not be a function of the type of VAD, but rather the catheter care protocols used in these patients. Clearly, this finding needs to be investigated further in future studies.
The majority of previous studies were conducted in Europe with one originating in Japan and none in the US. Only two studies, both by Cotogni et al. [18, 23], were conducted exclusively in cancer patients, while all other studies used a heterogeneous patient population with cancer patients being a subset of the entire study sample. Combining patients with different disease types can lead to erroneous conclusions regarding the incidence rate of CRBSI in a specific population of interest. Our study is different from the above studies in 2 important ways. Our study is the first observational study based out of the US using a large sample of cancer patients. We focused exclusively on cancer patients, 73% of whom were undergoing active oncologic treatments. This patient population is at a high-risk of experiencing CRBSI and has not been adequately investigated in the literature. Having said that, our study is very comparable to that by Cotogni et al.  in terms of the patient population investigated and the overall incidence rate of CRBSI reported (0.54 per 1000 HPN days in our study versus 0.60 per 1000 HPN days in the Cotogni study).
Unfortunately, HPN in the US is provided by multiple companies with variable level of expertise and experience. While ASPEN has come up with HPN guidelines, they are not mandated by any private or government insurance agencies. Once the insurer has approved HPN, any provider can deliver the services. This explains why there is a lack of good US-based studies reporting the incidence of CRBSI in HPN patients.
We also evaluated several factors for their association with the incidence of CRBSI. The factors investigated were type of VAD, age, gender, SGA, ECOG performance status, stage at diagnosis, BMI and serum albumin. Upon univariate analysis, no factors were found to be statistically significantly associated with the incidence of CRBSI.
Several risk factors for CRBSI have been reported in the literature. These factors either relate to the patient (type of underlying disease), or the type of VAD (catheter caliber, number of lumens), or the PN therapy (number of HPN days per week), or education (good training given to the patient and caregiver) or follow-up (involvement of a home care nurse) . However, no studies in the literature have investigated the association between baseline nutritional parameters and the risk of CRBSI. Serum albumin is a commonly used parameter to assess nutritional status in cancer and has been described as an independent prognosticator of survival in lung, pancreatic, gastric, colorectal, and breast cancers . In the hospital setting, higher levels of serum albumin have also been found to be correlated with lower in-hospital mortality, lower length of stay (LOS), higher quality of life, and lower rates of nosocomial infection [32, 33]. Although our study did not find a statistically significant association between serum albumin and the incidence of CRBSI, future studies should attempt to further explore this finding using larger sample sizes.
CRBSI is one of the most frequently occurring, extremely costly to treat and potentially life-threatening complications associated with the use of VADs. The risk of CRBSI is even higher in oncology patients who are actively receiving oncologic therapies due to their immunocompromised status. As a result, developing strategies that would prevent or minimize the incidence of CRBSIs has been a continual challenge for healthcare providers. Working in collaboration with a home infusion company that can help implement standardized catheter care protocol can potentially reduce the CRBSI incidence in such patients. These data can serve as a benchmark for potential use by other hospitals in preventing CRBSIs in these patients.
There are some limitations of this study which require careful acknowledgment. This was a retrospective observational study using data not primarily collected for research purposes. As a result, we did not have data available on all potential confounding variables (such as patient and caregiver training, involvement of a home care nurse, assessment of adherence to the catheter care protocol, patient educational status, patient smoking status, steroid use during treatment, liver function tests, and white blood cell counts) that could have impacted the incidence rate of CRBSI. Moreover, all VADs in our study were not specifically placed for the purpose of HPN. In some patients, VADs were initially placed for the purpose of delivering chemotherapy. However, we did not have data on the duration (or number of days) of VAD which can also potentially affect the occurrence of CRBSI. Our study population consisted of heterogeneous non-hospitalized patients with solid tumors from a single institution. As a result, the findings might not be generalizable to all cancer patients, especially those with hematological malignancies and those receiving HPN in a hospital setting. Finally, the humanistic and economic aspects related to the use of VADs were not investigated.
There are some strengths and unique features of our study. By using a consecutive case series of all eligible patients seen at our institution during a fixed time period, we minimized the possibility of selection bias in our study. Most of our patients were receiving active anticancer treatments while undergoing HPN. All VADs were inserted using the same evidence-based protocol and all patients received the same standardized catheter care protocol at home. Our study had a long follow-up period and no patients were lost to follow-up. To the best of our knowledge, this is the first and the largest US-based study reporting the incidence of and factors associated with CRBSI in a consecutive case series of non-hospitalized cancer patients undergoing HPN.