Economic burden of antibiotic treatment of healthcare-associated infections at a tertiary care hospital ICU in Goa,India

Introduction

Healthcare-associated infection (HCAI) is defined as: ‘An infection occurring in a patient during the process of care in a hospital or other health-care facility which was not present or incubating at the time of admission’. HCAI has replaced descriptions such as ‘nosocomial’ or ‘hospital-based’ infections, as these terms are non-inclusive. ¹ HCAIs may result in a length of stay in hospital for up to 10 days and thus increase the costs of hospitalisation.^2,3

It has been observed that approximately one in ten patients admitted to hospital suffer from one or more HCAIs at any one time. ⁴ The highest rates of HCAIs are observed in the intensive care unit (ICU), where the most severely ill patients are treated and where the highest mortality rates are observed. ⁵ The socioeconomic impact, owing to longer admissions, higher mortality and cost adversely affects patients’ as well as hospitals’ financial viability. ⁶ The cost of HCAIs includes increased length of hospital stay, staff time, laboratory investigations and antimicrobial treatment.^7,8

Antibiotics are among the most frequently used drugs in intensive care patients and thus account for a substantial proportion of drug expenditure in ICUs. ⁹ Although the cost of antimicrobial treatment is an important part of health expenditure, data on this subject are limited.

Antibiotic resistance and HCAIs are increasing problems in healthcare and have a significant impact on its cost-effectiveness. This is especially true in low- and middle-income countries, where the introduction of sophisticated and expensive healthcare tends to be given higher priority than the provision of basic measures such as infection control. ¹⁰

Studies to determine costs of illness are thus necessary to provide a comprehensive estimate of the impact of a disease on the healthcare system.

Methods

We performed a prospective analysis of HCAIs in the ICU of Goa Medical College Hospital, Bambolim Goa, from May 2011 to April 2012.

All adult patients aged over 15 years, ventilated or non-ventilated, admitted to the ICU were included in our study. Name, age, sex and diagnosis were noted.

The following were excluded: Neonatal and Paediatric ICU patients, patients with multiple HCAIs, and those with viral and fungal infections.

The main source of data was case papers and microbial culture and antibiotic sensitivity reports. HCAIs were determined according to the CDC definition. ¹¹ Infection sites and bacterial pathogens were isolated, antimicrobial treatment of patients and their cost were recorded. Antibiotic cost during the patients’ hospital stay was determined using the price list supplied by the hospital pharmacy.

Results

A total of 650 patients were admitted to the ICU with varying clinical conditions, both medical and surgical. Among these, 104 (of whom 66 were men) developed HCAIs and were included in the study. Fourteen developed multiple HCAIs and were excluded. The age and gender distribution of different HCAIs is shown in Table 1.

Ventilator-associated pneumonia (VAP) (50%) was found to be the most common HCAI, followed by urinary tract infection (UTI) (35.6%). Surgical site infection (SSI) (9.6%) and bloodstream infection (BSI) (4.8%) were the least prevalent.

The total of number of bacterial isolates was 188, of which 82.5% were accounted by Gram-negative bacilli and 17.5% Gram-positive cocci.

The bacterial species involved in different types of HCAIs are shown in Table 2.

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Table 1.

Age and gender distribution of different HCAIs.

		Type of HCAI				Total
		VAP (n = 52)	UTI (n = 37)	BSI (n = 5)	SSI (n = 10)	(n = 104)
Patient age (years)	16–30	11	8	0	4	25
	31–45	12	8	1	3	25
	46–60	13	11	1	2	21
	>60	16	10	3	1	33
Gender	Male	37	10	2	7	66
	Female	15	27	3	3	38

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Table 2.

Bacterial species involved in HCAIs.

Type of Microorganisms	Number (%)				Total (n)
	VAP	UTI	BSI	SSI
Pseudomonas aeruginosa	35 (33.6)	14 (31.1)	4 (20)	5 (26.3)	58 (30.8)
Staphylococcus aureus	14 (13.5)	7 (15.5)	6 (30)	4 (21)	31 (16.5)
Klebsiella species	12 (11.5)	6 (13.3)	2 (10)	2 (10.5)	22 (11.7)
Acinetobacter baumannii	18 (17.3)	–	2 (10)	2 (10.5)	22 (11.7)
Enterobacter species	8 (7.6)	9 (20)	3 (15)	1 (5.2)	21 (11.2)
Citrobacter species	10 (9.6)	1 (2)	1 (5)	1 (5.2)	13 (7)
Enterococcus species	4 (3.8)	2 (4)	2 (10)	1 (5.2)	9 (4.8)
Escherichia coli	1 (1)	5 (11.1)	–	3 (15.7)	9 (4.8)
Group D Streptococcus species	2 (1.9)	–	–	–	2 (1)
Proteus species	–	1 (2)	–	–	1 (0.5)
Total (n)	104 (55.3)	45 (24)	20 (10.6)	19 (10.1)	188 (100)

Overall, Pseudomonas aeruginosa (30.8%) was the most predominant organism isolated. Staphylococcus aureus (16.5%) was the next common isolate, followed by Klebsiella species (11.7%) and Acinetobacter baumannii (11.7%).

36% of antibiotic use in the ICU was for the treatment of HCAIs (17% confirmed and 19% suspected), 41% was for community-acquired infection (16% for confirmed and 25% for suspected) and 19% was prophylactic. The indication was unclear for 4%.

The rates of use of different antimicrobials for confirmed or suspected HCAIs and their costs are shown in Table 3.

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Table 3.

Antibiotics prescribed for HCAIs and their costs.

Sr. No.	Antimicrobials	Prescriptions (n = 208)	Total cost in Indian Rupees	Average cost per patient in Indian Rupees
1.	Amoxicillin + clavulanic acid	8	33,385	4173
2.	Piperacillin + tazobactam	12	152,884	12,740
3.	Ceftriaxone	6	8458	1410
4.	Ceftazidime	5	60,180	12,036
5.	Cefpirome	1	4900	4900
6.	Cefotaxime	1	1395	1395
7.	Cefoperazone + sulbactam	27	177,343	6568
8.	Ceftriaxone + sulbactam	7	21,500	3072
9.	Imipenem + cilastatin	13	280,476	21,575
10.	Meropenem	15	763,776	50,918
11.	Aztreonam	19	202,950	10,682
12.	Amikacin	17	196,027	11,531
13.	Netilmicin	1	5555	5555
14.	Ofloxacin	2	7803	3901
15.	Levofloxacin	3	1334	444
16.	Azithromycin	9	10,321	1146
17.	Clindamycin	10	34,104	3410
18.	Teicoplanin	8	141,825	17,728
19.	Linezolid	3	7788	2596
20.	Metronidazole	38	14,270	375
21.	Vancomycin	2	16,800	8400
	Total		2,143,074

A total of 208 courses of antibiotics were prescribed for HCAIs. Metronidazole (18.3%) was the most frequently prescribed followed by Cefoperazone sulbactam (13%) and Aztreonam (9%). A total of 72 courses were given as a combination of antimicrobials for greater coverage. The most common combinations were cefoperazone sulbactam + metronidazole (15 courses) followed by ceftriaxone + metronidazole (3 courses), meropenem + amikacin (3 courses), amoxicillin clavulanic acid + amikacin (3 courses) and cefoperazone sulbactam + aztreonam (3 courses).

The total cost of antibiotic treatment for HCAIs was approximately Rs. 2 million. The cost per patient of carbapenems was the highest; meropenem (Rs. 50,918) and imipenem cilastatin (Rs. 21,575). Teicoplanin (Rs. 17,728) and piperacillin tazobactam (Rs. 12,740) also accounted for a high cost.

The cost per patient for treating blood stream infections was the highest, followed by that for ventilator associated pneumonia (Table 4).

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Table 4.

Cost of the antibiotic therapy according to the site of infection.

Type of infection	Patients (n)	Total cost of antimicrobial therapy in Indian Rupees	Average cost per patient in Indian Rupees
VAP	52	1,198,913	23,056
UTI	37	626,942	16,944
BSI	5	215,061	43,012
SSI	10	90,252	9025

Discussion

Our study found the incidence of HCAIs in the ICU to be 16%. This is similar to values found in other studies in India,^12–14 the latter showing a somewhat lower incidence of 11.8%. A large meta-analysis reports a large variation in incidence from 2.3% to 49.2% across the centres studied. ¹⁵ This difference may be attributed to many factors including quality of care, infection control practices, precise definition and surveillance techniques, case mix, type of ICU, length of stay, rate of device utilisation and discharge criteria.^16–18

The specific microbial causes of HCAIs are many and varied. The relative prevalence of specific pathogens varies considerably depending on the characteristics of the patient population, duration of hospitalisation and mechanical ventilation and catheterisation prior to the onset of infection, prior exposure to antibiotic therapy and methods and criteria used for diagnosis. ¹⁹ The reasons for the preponderance of P. aeruginosa and A. baumanii are their ubiquitous nature, ease of adaptability and resistance to common disinfectants and antimicrobials that help these organisms to persist in the hospital environment and cause infections.

Among the antibiotics prescribed, 58.7% of prescriptions were started empirically whereas 41.3% were started after confirmation of the antibiotic sensitivity report, as in another study. ²⁰ Metronidazole was found to be the most frequently prescribed probably because anaerobic culture facilities in our practice are lacking and its empirical use was deemed justified where anaerobic infection was suspected. Expensive antibiotics such as carbapenems and beta lactamase inhibitor combinations were also seen to be used more frequently. Though the exact cause could not be determined, the severity of infection, the patient’s critical condition and multidrug resistance were probably the rationale.

A primary reason to calculate the cost of HCAI is to make informed decisions concerning the funds justified to allocate to infection control programmes.^21–24 The justifiable cost will vary depending on the institution.

The cost of therapy in our study may have been under-reported as we have excluded multiple HCAIs from our study. Moreover, to calculate the true overall costs of therapy, hidden costs arising from intravenous administration, labour, serum antibiotic assays, monitoring haematological and biochemical indices and adverse effects of antibiotics must be also considered. ²⁵ Our study does not include these relevant ‘hidden costs’ that would substantially increase the cost assessment. However, even without this, our argument holds.

Around one-third of HCAIs are preventable if the current infection control guidelines are followed properly. ²⁶ Hence, in our centre therefore an effective preventative programme costing Rs. 600,000 (US$9600) per year can readily be justified.

Furthermore, an antibiotic policy for HCAIs based on the latest antimicrobial sensitivity data and the judicious use of antibiotics will also diminish the socioeconomic burden of HCAIs.