Canadian Acute Care Hospitals Research Articles

Rural versus urban academic hospital mortality following stroke in Canada.

IntroductionStroke is one of the leading causes of death in Canada. While stroke care has improved dramatically over the last decade, outcomes following stroke among patients treated in rural hospitals have not yet been reported in Canada.ObjectivesTo describe variation in 30-day post-stroke in-hospital mortality rates between rural and urban academic hospitals in Canada. We also examined 24/7 in-hospital access to CT scanners and selected services in rural hospitals.Materials and methodsWe included Canadian Institute for Health Information (CIHI) data on adjusted 30-day in-hospital mortality following stroke from 2007 to 2011 for all acute care hospitals in Canada excluding Quebec and the Territories. We categorized rural hospitals as those located in rural small towns providing 24/7 emergency physician coverage with inpatient beds. Urban hospitals were academic centres designated as Level 1 or 2 trauma centres. We computed descriptive data on local access to a CT scanner and other services and compared mean 30-day adjusted post-stroke mortality rates for rural and urban hospitals to the overall Canadian rate.ResultsA total of 286 rural hospitals (3.4 million emergency department (ED) visits/year) and 24 urban hospitals (1.5 million ED visits/year) met inclusion criteria. From 2007 to 2011, 30-day in-hospital mortality rates following stroke were significantly higher in rural than in urban hospitals and higher than the Canadian average for every year except 2008 (rural average range = 18.26 to 21.04 and urban average range = 14.11 to 16.78). Only 11% of rural hospitals had a CT-scanner, 1% had MRI, 21% had in-hospital ICU, 94% had laboratory and 92% had basic x-ray facilities.ConclusionRural hospitals in Canada had higher 30-day in-hospital mortality rates following stroke than urban academic hospitals and the Canadian average. Rural hospitals also have very limited local access to CT scanners and ICUs. These rural/urban discrepancies are cause for concern in the context of Canada’s universal health care system.

A Walk in My Shoes: A Mixed-Method Study of the Role of Interprofessional Job Shadowing in Shaping Staff Attitudes at a Large Acute Care Hospital in Canada.

Poor hospital unit culture and staff morale, and dysfunctional multidisciplinary cooperation leads to worse patient safety and satisfaction. The Walk in My Shoes research project aimed to understand how interprofessional job shadowing impacts the attitudes of colleagues. Thirty-three registered nurses at an acute care hospital observed the daily work of social workers. Nurses' attitudes towards social workers were measured by surveys and interviews. Quantitative data indicated a change in nurses' perception of social workers' communication, teamwork and autonomy. Qualitative data indicate that job shadowing helped participants identify personal misperceptions, provided new understanding of roles and gave insight into co-worker job similarities.

The My Meal Intake Tool (M-MIT): Validity of a Patient Self- Assessment for Food and Fluid Intake at a Single Meal.

Hospital malnutrition is an under-recognized issue that leads to a variety of adverse outcomes, especially for older adults. Food/fluid intake (FFI) monitoring in hospital can be used to identify those who are improving and those who need further treatment. Current monitoring practices such as calorie counts are impractical for all patients and a patient-completed tool, if valid, could support routine FFI monitoring. The aim of this research was to determine whether the patient-completed My Meal Intake Tool (M-MIT) can accurately represent FFI at a single meal. Cross-sectional, multi-site. Four acute care hospitals in Canada. 120 patients (65+ yrs, adequate cognition). Participants completed M-MIT for a single meal. Food and fluid waste was visually estimated by a research dietitian at each hospital. Sensitivity (Se), specificity (Sp) and overall agreement were calculated for both food and fluid intake by comparing M-MIT and dietitian estimations to determine criterion validity of M-MIT. Patient and research dietitian comments were used to make revisions to the M-MIT. Using a cut-point of ≤50% intake, Se was 76.2% and 61.9% and Sp was 74.0% and 80.5% for solid and fluids respectively (p<0.001). M-MIT identified a greater proportion of participants (37.2%) as having low FFI (≤50%) than dietitians (25.0%), as well as a greater proportion identified with low fluid intake (28.3% vs. 24.6%). Modest revisions were made to improve the tool. This study has demonstrated initial validity of M-MIT for use in older patients with adequate cognition. Use of M-MIT could promote FFI monitoring as a routine practice to make clinical decisions about care.

A mixed-methods pilot study of the factors that influence collaboration among registered nurses and registered practical nurses in acute care

Objective: Staffing models employing registered nurses (RNs) and registered practical nurses (RPN) have created the opportunity for enhanced collaboration in acute care settings. However, little is understood about how these nurses collaborate and the factors that influence their collaboration. The purpose of this pilot study was to examine the factors that influenced collaboration among RNs and RPNs at one acute care hospital in Canada in order to understand and improve nursing collaborative practice.Methods: Using an explanatory, sequential mixed methods design, data were collected over several months in 2016 from the nurses using a questionnaire and individual telephone interviews. Sixty-five RNs and RPNs working on medical, surgical and emergency units completed the “Nurse-Nurse Collaboration Scale” survey and ten RNs and RPNs participated in the telephone interviews.Results: Quantitative analysis showed lower scores among younger nurses across most domains of the survey: conflict management, communication, shared processes, coordination and professionalism. Qualitative analysis revealed working to full scope of practice was a facilitator of RN-RPN collaboration, and older age and poor interpersonal skills were barriers to successful collaboration.Conclusions: The results provide discussion for identification of strategies to improve collaborative practice among nurses such as establishing joint education programs for RNs and RPNs, and the use of models or frameworks to guide collaborative practice in healthcare organizations.

The Mealtime Audit Tool (MAT) - Inter-Rater Reliability Testing of a Novel Tool for the Monitoring and Assessment of Food Intake Barriers in Acute Care Hospital Patients.

Barriers to food intake (FI) exist in hospital that could exacerbate insufficient FI and malnutrition. The Mealtime Audit Tool (MAT) is a staff-administered clinical assessment tool to identify FI barriers for individual patients. Two studies were completed. The objectives of the first study were to test a draft version of the tool and characterize barriers to food intake in older adults in four diverse hospitals, while the second study aimed to demonstrate the inter-rater reliability of the revised MAT. Multi-site, cross sectional. Four acute care hospitals in Canada. Study 1: 120 older (65+ years, adequate cognition) medical or surgical patients. Study 2: 90 medical or surgical patients. In study 1, participants had barriers experienced at one mealtime assessed with MAT. Descriptive analyses characterized the prevalence of barriers across the hospitals. Revisions were made to the MAT based on recommendations from sites. A revised version was tested for inter-rater reliability in study 2. Intraclass correlation coefficient (ICC) was calculated for total MAT scores from 90 patient meals assessed by two raters. Kappa statistics were calculated for each of the 18 MAT items. Mean (+/- standard deviation) number of barriers experienced in Study 1 was 2.93 +/- 1.58, and in Study 2 was 2.51 +/- 1.19. The revised MAT was reliable with an ICC of 0.68 (95%CI: 0.52-0.79). Ten of 16 items in which kappa could be calculated had at least fair agreement. MAT is sufficiently reliable when used by auditors with minimal training. Routinely auditing mealtimes with MAT could be useful in identifying and removing barriers to food intake for older hospitalized patients.

Variability in antibiotic use across Ontario acute care hospitals.

Antibiotic stewardship is a required organizational practice for Canadian acute care hospitals, yet data are scarce regarding the quantity and composition of antibiotic use across facilities. We sought to examine the variability, and risk-adjusted variability, in antibiotic use across acute care hospitals in Ontario, Canada's most populous province. Antibiotic purchasing data from IMS Health, previously demonstrated to correlate strongly with internal antibiotic dispensing data, were acquired for 129 Ontario hospitals from January to December 2014 and linked to patient day (PD) denominator data from administrative datasets. Hospital variation in DDDs/1000 PDs was determined for overall antibiotic use, class-specific use and six practices of clinical or ecological significance. Multivariable risk adjustment for hospital and patient characteristics was used to compare observed versus expected utilization. There was 7.4-fold variability in the quantity of antibiotic use across the 129 acute care hospitals, from 253 to 1873 DDDs/1000 PDs. Variation was evident within hospital subtypes, exceeded that explained by hospital and patient characteristics, and included wide variability in proportion of broad-spectrum antibiotics (IQR 36%-48%), proportion of fluoroquinolones among respiratory antibiotics (IQR 40%-62%), proportion of ciprofloxacin among urinary anti-infectives (IQR 44%-60%), proportion of antibiotics with highest risk for Clostridium difficile (IQR 29%-40%), proportion of 'reserved-use' antibiotics (IQR 0.8%-3.5%) and proportion of anti-pseudomonal antibiotics among antibiotics with Gram-negative coverage (IQR 26%-40%). There is extensive variability in antibiotic use, and risk-adjusted use, across acute care hospitals. This could motivate, focus and benchmark antibiotic stewardship efforts.

Discordance between patients' stated values and treatment preferences for end-of-life care: results of a multicentre survey

BackgroundMedical orders for the use of life-supports should be informed by patients' values and treatment preferences. The purpose of this study was to explore the internal consistency of patients' (or...

Human resource management practices and nursing turnover

Background: The objective of this study is to explore the nature of the association of discrete systems of human resource management practices and the rate of voluntary turnover of registered nurses (RNs) in a large sample of Canadian acute care hospitals and nursing homes. Turnover of nursing staff is a significant issue affecting healthcare cost, quality and access. The rate of annual turnover for registered nurses has been estimated to be about 20 percent in Canada, with a total cost of almost US$27,000 for each RN. Healthcare organizations that employ large numbers of registered nurses are keen to learn more about the role that organizational policies and practices play in reducing voluntary turnover, including the role of management and its deployment of human resources. The relationship of human resource management (HRM) practices and employee turnover has generally been under-investigated. Three HRM systems, composed of bundles of discrete workplace and employment practices, were assembled in order to assess the relationship of HRM practice systems with the rate of voluntary RN turnover, at the establishment level. The three HRM practice systems constructed are: a technical HRM system that focuses on policies and practices that regulate the employee-employer relationship; a quality-of-worklife HRM system that includes a variety of employee- and family-friendly employment practices; a high-involvement HRM system that involve workplace arrangements that increase commitment, engagement and participation of employees. Method and analysis: A questionnaire was sent to the chief nursing officers of 2,208 hospitals and long-term care facilities in every province and territory of Canada, yielding valid responses from 705 establishments. Each of the three HRM practice systems is estimated at each facility and comprises eight (8) discrete employment and workplace practices. Using estimates of voluntary RN turnover as the dependent variable, the analysis featured a step-wise ordinary least squares (OLS) regression model for each practice system. Results: After controlinf for facility characteristics and local labour market conditions, the quality-of-worklife HRM employment system ( p <.05) and high-involvement HRM works system ( p <.05) are found to be associated with lower voluntary turnover, yet their overall relationship with facility turnover appears to be quite modest. Our technical HRM system is not found to be associated with facility RN turnover. Conclusion: HRM systems comprising employee-friendly employment practices and nursing high-involvement work practices may play a significant (yet modest) role in reducing RN turnover.

Assessing the magnitude and trends in hospital acquired infections in Canadian hospitals through sequential point prevalence surveys.

BackgroundHealthcare acquired infections (HAI) are an important public health problem in developed countries, but comprehensive data on trends over time are lacking. Prevalence surveys have been used as a surrogate for incidence studies and can be readily repeated.MethodsThe Canadian Nosocomial Infection Surveillance Program conducted prevalence surveys in 2002 and 2009 in a large network of major Canadian acute care hospitals. NHSN definitions of HAI were used. Use of isolation precautions on the survey day was documented.ResultsIn 2009, 9,953 acute care inpatients were surveyed; 1,234 infections (124/1000) were found, compared to 111/1000 in 2002, (p < 0.0001). There was increased prevalence of urinary tract infection (UTI) and Clostridium difficile, offset by decreases in pneumonia and bloodstream infection. Use of isolation precautions increased from 77 to 148 per 1000 patients (p < 0.0001), attributable to increased use of contact precautions in patients infected or colonized with antimicrobial resistant organisms.ConclusionBetween 2002 and 2009 HAI prevalence increased by 11.7 % in a network of major Canadian hospitals due to increases in Clostridium difficile and urinary tract infection. The use of isolation precautions increased by 92.2 % attributable to increased contact isolation. National prevalence surveys are useful tools to assess evolving trends in HAI.

Clinical characteristics and preventable acute care spending among a high cost inpatient population.

BackgroundA small proportion of patients account for the majority of health care spending. The objectives of this study were to explore the clinical characteristics, patterns of health care use, and the proportion of acute care spending deemed potentially preventable among high cost inpatients within a Canadian acute-care hospital.MethodsWe identified all individuals within the Ottawa Hospital with one or more inpatient hospitalization between April 1, 2010 and March 31, 2011. Clinical characteristics and frequency of hospital encounters were captured in the information systems of the Ottawa Hospital Data Warehouse. Direct inpatient costs for each encounter were summed using case costing information and those in the upper first and fifth percentiles of the cumulative direct cost distribution were defined as extremely high cost and high cost respectively. We quantified preventable acute care spending as hospitalizations for ambulatory care sensitive conditions (ACSC) and spending attributable to difficulty discharging patients as measured by alternate level of care (ALC) status.ResultsDuring the study period, 36,892 patients had 44,066 hospitalizations. High cost patients (n = 1,844) accounted for 38 % of total inpatient spending ($122 million) and were older, more likely to be male, and had higher levels of co-morbidity compared to non-high cost patients. In over half of the high cost cohort (54 %), costs were accumulated from a single hospitalization. The majority of costs were related to nursing care and intensive care unit spending. High cost patients were more likely to have an encounter deemed to be ambulatory care sensitive compared to non-high cost inpatients (6.0 versus 2.8 %, p < 0.001). A greater proportion of inpatient spending was attributable to ALC days for high cost versus non-high cost patients (9.1 versus 4.9 %, p < 0.001).ConclusionsWithin a population of high cost inpatients, the majority of costs are attributed to a single, non-preventable, acute care episode. However, there are likely opportunities to improve hospital efficiency by focusing on different approaches to community based care directed towards specific populations.Electronic supplementary materialThe online version of this article (doi:10.1186/s12913-016-1418-2) contains supplementary material, which is available to authorized users.

Critical care capacity in Canada: results of a national cross-sectional study.

IntroductionIntensive Care Units (ICUs) provide life-supporting treatment; however, resources are limited, so demand may exceed supply in the event of pandemics, environmental disasters, or in the context of an aging population. We hypothesized that comprehensive national data on ICU resources would permit a better understanding of regional differences in system capacity.MethodsAfter the 2009–2010 Influenza A (H1N1) pandemic, the Canadian Critical Care Trials Group surveyed all acute care hospitals in Canada to assess ICU capacity. Using a structured survey tool administered to physicians, respiratory therapists and nurses, we determined the number of ICU beds, ventilators, and the ability to provide specialized support for respiratory failure.ResultsWe identified 286 hospitals with 3170 ICU beds and 4982 mechanical ventilators for critically ill patients. Twenty-two hospitals had an ICU that routinely cared for children; 15 had dedicated pediatric ICUs. Per 100,000 population, there was substantial variability in provincial capacity, with a mean of 0.9 hospitals with ICUs (provincial range 0.4-2.8), 10 ICU beds capable of providing mechanical ventilation (provincial range 6–19), and 15 invasive mechanical ventilators (provincial range 10–24). There was only moderate correlation between ventilation capacity and population size (coefficient of determination (R2) = 0.771).ConclusionICU resources vary widely across Canadian provinces, and during times of increased demand, may result in geographic differences in the ability to care for critically ill patients. These results highlight the need to evolve inter-jurisdictional resource sharing during periods of substantial increase in demand, and provide background data for the development of appropriate critical care capacity benchmarks.Electronic supplementary materialThe online version of this article (doi:10.1186/s13054-015-0852-6) contains supplementary material, which is available to authorized users.

Estimated hospitalizations attributed to norovirus and rotavirus infection in Canada, 2006–2010

Enteric viruses including norovirus and rotavirus are leading causes of gastroenteritis in Canada. However, only a small number of clinical cases are actually tested for these pathogens leading to systematic underestimation of attributed hospitalizations in administrative databases. The objective of this analysis was to estimate the number of hospitalizations due to norovirus and rotavirus in Canada. Hospitalization records for acute gastroenteritis-associated discharges at all acute-care hospitals in Canada between 2006 and 2011 were analysed. Cause-unspecified gastroenteritis hospitalizations were modelled using age-specific negative binomial models with cause-specified gastroenteritis admissions as predictors. The coefficients from the models were used to estimate the number of norovirus and rotavirus admissions. The total annual hospitalizations for rotavirus were estimated to be between 4500 and 10 000. Total annual hospitalizations for norovirus were estimated to be between 4000 and 11 000. The mean total annual cost associated with these hospitalizations was estimated to be at least $16 million for rotavirus and $21 million for norovirus (all figures in Canadian dollars). This study is the first comprehensive analysis of norovirus and rotavirus hospitalizations in Canada. These estimates provide a more complete assessment of the burden and economic costs of these pathogens to the Canadian healthcare system.

The implementation of Ebola personal protective equipment training in a large Canadian acute care hospital

Effective use of personal protective equipment (PPE) is essential to protect personnel and patients in health care settings. However, in a survey of 222 health care personnel, PPE training was often suboptimal with no requirement for demonstration of proficiency. Fourteen percent of physicians reported no previous training in use of PPE.

An environmental scan of medical assessment units in Canada.

Many initiatives have been proposed to improve emergency department (ED) overcrowding. One such strategy has been to implement medical assessment units (MAUs). This study reports on an environmental scan of MAU distribution and characteristics across Canada. A telephone survey was administered to administrative and clinical leaders at acute-care hospitals in Canada. The survey was designed in two sections: (1) description of hospital and ED characteristics; and (2) description of any existing MAU-like units associated with the hospital's ED structure and processes. Our survey reveals that MAU-like initiatives exist in several Canadian hospitals but are heterogeneous in structure and functionality.

End-of-life hospital care for cancer patients: an update.

Cancer is the leading cause of death in Canada, and the number of new cases is expected to increase as the population ages and grows. This study examined the use of hospital services in the last month of life by adult cancer patients who died in Canadian acute care hospitals in fiscal year 2012-2013. Almost 25,000 Canadian cancer patients - excluding those in Quebec - died in acute care hospitals, representing approximately 45% of the estimated cancer deaths in 2012-2013. The proportion of in-hospital deaths varied across jurisdictions. Twenty-three percent of these patients were admitted to acute care multiple times in their last 28 days of life, with a higher percentage for rural (29%) compared to urban (21%) patients. Relatively few patients used intensive care units or received inpatient chemotherapy in their last 14 days of life.

A data envelopment analysis approach for measuring the efficiency of Canadian acute care hospitals

Data envelopment analysis is a methodology particularly well-suited to measuring the efficiency of hospitals because it is able to accommodate multiple heterogeneous inputs and outputs in order to model the complex relationships that exist within them. This research uses data envelopment analysis to develop a model of Canadian hospital production efficiency in collaboration with the Canadian Institute for Health Information. The model is intended to illustrate the utility of data envelopment analysis as a hospital performance measurement tool for Canadian Institute for Health Information and to augment their current hospital performance indicators. The model measures the overall production efficiency of acute care hospitals using labour and capital inputs together with outputs measuring inpatient and outpatient activity. The model also includes non-discretionary variables adjusting for case-mix variations among the hospitals. The model is extensively validated and identifies a set of highly referenced, efficient hospitals ideal for the establishment of best practices.

Environmental cleaning resources and activities in Canadian acute care hospitals

Environmental cleaning interventions have increased cleaning effectiveness and reduced antibiotic-resistant organisms in hospitals. This study examined cleaning in Canadian acute care hospitals with the goal of developing strategies to improve cleaning and reduce antibiotic-resistant organism rates. Managers most responsible for environmental services (EVS) completed an extensive online survey that assessed EVS resources and cleaning practices. The response rate was 50.5%; 96 surveys were completed, representing 103 of 204 hospitals. Whereas 86.3% (82/95) of managers responsible for EVS reported their staff was adequately trained and 76.0% (73/96) that supplies and equipment budgets were sufficient, only 46.9% (45/96) reported that EVS had enough personnel to satisfactorily clean their hospital. A substantial minority (36.8%, 35/95) of EVS departments did not audit the cleaning of medical surgical patient rooms on at least a monthly basis. Cleaning audits of medical surgical patient rooms frequently included environmental marking methods in only one third (33.3%, 31/93) of hospitals and frequently included the measurement of residual bioburden in only 13.8% (13/94). There was a general need for increased and improved auditing of environmental cleaning in Canadian hospitals, and there were perceived EVS staffing deficits in the majority of hospitals.

Working relationships of infection prevention and control programs and environmental services and associations with antibiotic-resistant organisms in Canadian acute care hospitals

Environmental contamination in hospitals with antibiotic-resistant organisms (AROs) is associated with patient contraction of AROs. This study examined the working relationship of Infection Prevention and Control (IPAC) and Environmental Services and the impact of that relationship on ARO rates. Lead infection control professionals completed an online survey that assessed the IPAC and Environmental Services working relationship in their acute care hospital in 2011. The survey assessed cleaning collaborations, staff training, hospital cleanliness, and nosocomial methicillin-resistant Staphylococcus aureus (MRSA) infection, vancomycin-resistant Enterococcus (VRE) infection, and Clostridium difficile infection (CDI). The survey was completed by 58.3% of hospitals (119 of 204). Two-thirds (65.8%; 77 of 117) of the respondents reported that their cleaners were adequately trained, and 62.4% (73 of 117) reported that their hospital was sufficiently clean. Greater cooperation between IPAC and Environmental Services was associated with lower rates of MRSA infection (r = -0.22; P = .02), and frequent collaboration regarding cleaning protocols was associated with lower rates of VRE infection (r = -0.20; P = .03) and CDI (r = -0.31; P < .001). Canadian IPAC programs generally had collaborative working relationships with Environmental Services, and this was associated with lower rates of ARO. Deficits in the adequacy of cleaning staff training and hospital cleanliness were identified. The promotion of collaborative working relationships and additional training for Environmental Services workers would be expected to lower ARO rates.

Patient safety and professional discourses: implications for interprofessionalism

Patient safety has been presented as a unifying concern across the health professions. This conceptual connection has been accompanied with efforts towards standardized, interprofessional safety competencies, as well as increased attention towards interprofessional education for systems improvement. Despite numerous program initiatives and research endeavors, progress towards improving patient safety in hospitals is viewed as disappointingly slow. This paper adds to a body of literature that suggests patient safety remains a difficult problem to solve because safety is not simply a technical issue, but is a practice embedded in organizational and professional contexts. In this paper, we explore the differences between the professions, as different professional groups intersect with the ways patient safety is thought about, talked about, and known about in an acute care hospital in Canada. We draw on findings from a critical discourse analysis of documents related to patient safety, as well as transcripts from interviews from (a) formal health care leaders and (b) practicing clinicians from medicine, nursing, occupational therapy, physiotherapy, and social work. This analysis suggests implications for the way different professions may or may not work with one another in the service of patient safety.

Population-based analysis of blunt splenic injury management in children: Operative rate is an informative quality of care indicator

BackgroundIn hemodynamically normal children with blunt splenic injury (BSI), the standard of care is non-operative management. Several studies have reported that non-paediatric and non-trauma centres have higher operative rates in children with BSI compared to paediatric hospitals and trauma centres. We investigate the feasibility of using operative rate for BSI as a quality of care indicator. MethodsWe performed a population-based retrospective cohort study of children (≤18 years) with BSI admitted to all acute-care hospitals in Canada from 2001 to 2010. The main outcome was rate of operative management for BSI. Hierarchical multivariable logistic regression models were constructed to evaluate the relationship between operative rate and different hospital types (paediatric or non-paediatric, trauma or non-trauma). These models also allowed for generation of hospital-level observed to expected (O/E) ratios for rate of operative management. ResultsWe identified 3122 children with BSI. The majority (74%) were isolated splenic injuries and the grade of splenic injury was specified in 45% of cases (n=1391, 38% grade I or II; 62% grade III, IV, or V). The overall operative rate was 11% (n=315), of which 9% were total splenectomy and 2% were spleen-preserving operations. After adjusting for age, gender, mechanism of injury, splenic injury grade, ISS, and centre volume, admission to non-paediatric hospitals was associated with a higher probability of operative management (OR 7.6, 95% CI 2.4–24.4), whereas there was no significant difference in operative management between trauma and non-trauma centres (OR 1.6, 95% CI 0.8–3.2). Outlier status based on O/E ratio was determined to identify centres with higher or lower than expected operative rates. ConclusionsThe operative rates for children with BSI are significantly higher in non-paediatric hospitals. In these hospitals that do not routinely care for children and have higher than expected operative rates, we have used operative rate for BSI as a quality of care indicator and identified opportunities for quality improvement initiatives.Level of evidence: III, Retrospective comparative study.