Contact precautions (CPs) are basic infection control practices to prevent transmission of pathogens, particularly of multidrug-resistant bacteria and specific enteric and/or viral pathogens.Reference Siegel, Rhinehart, Jackson and Chiarello 1 , Reference Siegel, Rhinehart, Jackson and Chiarello 2 Although several studies have assessed the effectiveness and potential complications of CPs,Reference Siegel, Rhinehart, Jackson and Chiarello 1 – Reference Cohen, Cohen and Shang 4 little is known about their actual costs, particularly in a nonoutbreak setting. Therefore, we aimed to calculate the daily direct costs of CPs during a nonoutbreak period.
METHODS
From March through May 2017, we conducted a prospective study to evaluate additional costs for CPs at the University Hospital Basel, an 800-bed tertiary-care center in Switzerland. During the study period, we randomly chose 10 patients with ongoing CPs, who were hospitalized on any of our medical or surgical acute-care wards, for on-site observation of isolation activities. Patients with airborne precautions were not included in the study. The local ethics committee approved the study as part of a continuing quality improvement program.
For each of these 10 patients, the corresponding isolation activities were observed for 24 consecutive hours by infection practitioners and well-trained medical students who were situated in front of the patient’s room. During observation periods, materials used, and extra workload relating to CPs were prospectively recorded and itemized. Standard care activities were not included if they were not part of standard precautions recommended by the Centers for Disease Control and Prevention (CDC).Reference Siegel, Rhinehart, Jackson and Chiarello 1
From the hospital’s perspective, direct costs of CPs were calculated per patient day based on the following cost items: (1) additional isolation materials, (2) additional cleaning and disinfection materials, (3) extra workload (differentiated by hospital staff category), and (4) one-off items.
All costs were calculated in Swiss francs and converted to US dollars using the exchange rate of April 1, 2017, which was close to 1:1 (1 Swiss franc=$0.9973). Material costs were calculated based on manufacturers’ catalog prices. Costs of extra workload were calculated per minute, stratified by hospital staff category and based on actual mean gross wages (including the employer’s social security contributions) in January–February 2017. The (direct) cost items, respective costs, and gross wages are presented in Supplementary Table S1.
Direct costs were defined as additional costs that were directly attributable to CPs: costs of additional materials used, labor, and all direct efforts relating to CPs.Reference Siegel, Rhinehart, Jackson and Chiarello 1 Additional isolation and cleaning and disinfection materials were defined as any resources specifically used as part of the CPs.Reference Siegel, Rhinehart, Jackson and Chiarello 1 Extra workload was defined as any activity of healthcare workers or hospital staff that were directly attributable to CPs (eg, donning gowns and gloves upon entering the patient’s room).Reference Siegel, Rhinehart, Jackson and Chiarello 1 One-off costs (averaged for the individual length of CPs per case) were defined as any fixed costs arising at the first or last day of CPs that were linked to CPs, including actual costs of an intensified final room disinfection and curtain changes (ie, service charges) and estimated (ie, one-off) extra workload. A consensus estimate of one-off workload (fixed) was based on internal interviews: 30 minutes for infection preventionists, 30 minutes for nurses (preparation of patient room), and 5 minutes for each board-certified physician and resident. The daily compliance rate of hospital staff was defined as the proportion of hospital staff entering a patient room that carried out all CDC-recommended CPs upon entering and leaving the respective patient room.Reference Siegel, Rhinehart, Jackson and Chiarello 1
After ten 24-hour observations, we stopped including further patients due to a low variability of daily direct costs of CPs in a predefined interim analysis. The mean direct costs per patient day totaled $158.90 (95% confidence interval [CI], $124.90‒$192.80; 1,000-fold bootstrap 95% CI, $126.70‒$193.20). All cost data are expressed as mean (95% CI) to ensure the comprehensibility of cost calculations; additionally, skewed cost data are presented as median (interquartile range [IQR]). We analyzed all data using SPSS software version 22 (IBM, Chicago, IL).
RESULTS
For 10 patients with CPs, isolation activities were directly observed and itemized for 24 hours during a nonoutbreak period (Supplementary Table S1). Among these patients, 9 were isolated due to colonization with a multidrug-resistant or extended-spectrum β-lactamase-producing pathogen; the remaining patient had hypervirulent C. difficile ribotype 027 and associated diarrhea (Supplementary Table S2).
Per patient day on a medical (n=4 patients) or surgical acute-care ward (n=6 patients), the mean direct costs of CPs were $158.90 (95% CI, $124.90‒$192.80), with the average extra cost differing significantly across cost categories: isolation materials (mean, $43.1; 95% CI, $33.80‒$52.40), cleaning and disinfection materials (mean, $5.30; 95% CI, $4.00‒$6.60), extra workload for all hospital staff categories (mean, $88.80; 95% CI, $67.70‒$110.00), and one-off costs (median, $11.90; IQR, $4.40‒$16.70) (P < .001; Table 1). Overall, the mean daily rate of compliance to CDC-recommended CPs was 90.5% (95% CI, 84.8%‒96.2%).
TABLE 1 Cost Items and Respective Direct Costs of Contact Precautions per Patient Day on Medical and Surgical Wards (N=10 Patient Days)
NOTE. CI, confidence interval; IQR, interquartile range.
a The average direct costs differed significantly across cost categories, ie, isolation materials, cleaning/disinfection materials, extra workload (all hospital staff categories), and one-off costs (P < .001 by Kruskal-Wallis test).
b Includes the extra workload of nurses, physicians, and any other hospital staff (eg, cleaning staff) that were directly attributable to the contact precautions (eg, gowning/gloving upon entering the patient’s room).
c For each patient, one-off costs (averaged for individual length of a contact precaution case) were calculated as fixed costs arising at the first or last day of contact precautions, including costs of an intensified final room disinfection/curtain changes (service charge) and estimated (one-off) extra workload. Total one-off costs/charges (not averaged): $50.00 per intensified final room disinfection, $450.00 per hydrogen peroxide vaporization, and $68.30 for extra one-off workload.
DISCUSSION
In this cost analysis, we calculated the direct costs of CPs per patient day on the acute-care wards of a tertiary-care hospital; these cost data may be important in precise cost-effectiveness analyses comparing different isolation strategies and to adequately informing health policy makers and hospital administrators about direct costs of isolation measures in nonoutbreak settings.Reference Birgand, Moore and Bourigault 5 Moreover, our observations of isolation activities may be used to inform healthcare workers about the average extra workload due to CPs, which is essential to guarantee adequate staffing levels.
Our cost estimates for CPs were much higher than in other studies.Reference Verlee, Berriel-Cass, Buck and Nguyen 6 , Reference Papia, Louie, Tralla, Johnson, Collins and Simor 7 Based on the daily use of gowns, a study approximated the number of patient room entries and consecutively estimated the mean direct costs of CPs (for gowns and gloves and workload for donning and doffing protective equipment) to be $34.70 (95% CI, $31.40‒$37.60) per inpatient day.Reference Verlee, Berriel-Cass, Buck and Nguyen 6 However, this study did not account for extra material used other than gloves and gowns and included only costs of extra staff time for donning and doffing protective equipment. Furthermore, in a study assessing the cost-effectiveness of admission screenings for methicillin-resistant Staphylococcus aureus, mean direct costs of CPs were assumed to be 57.60 Canadian dollars per patient day, including costs of gowns and gloves and nursing time to don, doff, and discard gloves and gowns.Reference Papia, Louie, Tralla, Johnson, Collins and Simor 7 In our study, a main cost driver for CPs was the extra workload of healthcare workers, particularly of nurses and assistant nurses, and the use of isolation materials (Supplementary Table S1/Table 1), which may be difficult to quantify in retrospect.
Our study has several limitations. First, our analysis was based on ten 24-hour observations, which might not account for the entire spectrum of direct costs arising from CPs. Furthermore, salaries for healthcare workers in Switzerland are higher than in most other countries; therefore, adjustments to our estimates may be required for calculation of individual hospital-based costs. Also, our study was not intended or designed to estimate the potential loss of revenue associated with CPs and respective bed closures or increases in length of hospital stay, which constitute highly variable indirect costs that had previously been approximated to be ~$350 per blocked bed day.Reference Hubner, Hubner and Muhr 8 In addition, our cost calculations were performed for medical and surgical wards, excluding intermediate and intensive care units, where isolation costs might be higher.Reference Verlee, Berriel-Cass, Buck and Nguyen 6 Finally, depending on the hospital and patient setting, total extra costs of CPs might be much higher, particularly when accounting for indirect costs such as potential infrastructure costs and missed revenue due to bed closures.Reference Birgand, Moore and Bourigault 5
In conclusion, in this prospective cost analysis, mean direct costs of CPs were $158.90 per patient day (95% CI, $124.90‒$192.80), including costs of additional materials, extra workload, and one-off isolation activities. This number is an advanced estimate of direct isolation activities that substantiates additional costs of CPs for the prevention of multidrug-resistant organism transmission.
ACKNOWLEDGMENTS
Financial support: This work was funded by the Division of Infectious Diseases and Hospital Epidemiology, University Hospital Basel, Basel, Switzerland. No external funding was received.
Potential conflicts of interest: All authors report no conflicts of interest relevant to this article.
SUPPLEMENTARY MATERIAL
To view supplementary material for this article, please visit https://doi.org/10.1017/ice.2017.258.
