Moving Forward in GME Reform: A 4 + 1 Model of Resident Ambulatory Training

BACKGROUND

Traditional ambulatory training models have limitations in important domains, including opportunities for residents to learn, fragmentation of care delivery experience, and satisfaction with ambulatory experiences. New models of ambulatory training are needed.

AIM

To compare the impact of a traditional ambulatory training model with a templated 4 + 1 model.

SETTING

A large university-based internal medicine residency using three different training sites: a patient-centered medical home, a hospital-based ambulatory clinic, and community private practices.

PARTICIPANTS

Residents, faculty, and administrative staff.

PROGRAM DESCRIPTION

Development of a templated 4 + 1 model of residency where trainees do not attend to inpatient and outpatient responsibilities simultaneously.

PROGRAM EVALUATION

A mixed-methods analysis of survey and nominal group data measuring three primary outcomes: 1) Perception of learning opportunities and quality of faculty teaching; 2) Reported fragmentation of care delivery experience; 3) Satisfaction with ambulatory experiences. Self-reported empanelment was a secondary outcome. Residents’ learning opportunities increased (p = 0.007) but quality of faculty teaching was unchanged. Participants reported less fragmentation in the care residents provide patients in the inpatient and outpatient setting (p < 0.0001). Satisfaction with ambulatory training improved (p < 0.0001). Self-reported empanelment also increased (p < 0.0001). Results held true for residents, faculty, and staff at all three ambulatory training sites (p < 0.0001).

DISCUSSION

A 4 + 1 model increased resident time in ambulatory continuity clinic, enhanced learning opportunities, reduced fragmentation of care residents provide, and improved satisfaction with ambulatory experiences. More studies of similar models are needed to evaluate effects on additional trainee and patient outcomes.

Electronic supplementary material

The online version of this article (doi:10.1007/s11606-013-2387-3) contains supplementary material, which is available to authorized users.KEY WORDS: ambulatory training, 4 + 1 model     

Does Improved Continuity of Primary Care Affect Clinician–Patient Communication in VA?

BACKGROUND

Recent changes in health care delivery may reduce continuity with the patient’s primary care provider (PCP). Little is known about the association between continuity and quality of communication during ongoing efforts to redesign primary care in the Veterans Administration (VA).

OBJECTIVE

To evaluate the association between longitudinal continuity of care (COC) with the same PCP and ratings of patient–provider communication during the Patient Aligned Care Team (PACT) initiative.

DESIGN

Cross-sectional survey.

PARTICIPANTS

Four thousand three hundred ninety-three VA outpatients who were assigned to a PCP, had at least three primary care visits to physicians or physician extenders during Fiscal Years 2009 and 2010 (combined), and who completed the Survey of Healthcare Experiences of Patients (SHEP) following a primary care visit in Fiscal Year (FY)2011.

MAIN MEASURES

Usual Provider of Continuity (UPC), Modified Modified Continuity Index (MMCI), and duration of PCP care were calculated for each primary care patient. UPC and MMCI values were categorized as follows: 1.0 (perfect), 0.75–0.99 (high), 0.50–0.74 (intermediate), and < 0.50 (low). Quality of communication was measured using the four-item Consumer Assessment of Healthcare Providers and Systems-Health Plan program (CAHPS-HP) communication subscale and a two-item measure of shared decision-making (SDM). Excellent care was defined using an “all-or-none” scoring strategy (i.e., when all items within a scale were rated “always”).

KEY RESULTS

UPC and MMCI continuity remained high (0.81) during the early phase of PACT implementation. In multivariable models, low MMCI continuity was associated with decreased odds of excellent communication (OR?=?0.74, 95 % CI?=?0.58–0.95) and SDM (OR?=?0.70, 95 % CI?=?0.49, 0.99). Abbreviated duration of PCP care (< 1 year) was also associated with decreased odds of excellent communication (OR?=?0.35, 95 % CI?=?0.18, 0.71).

CONCLUSIONS

Reduced PCP continuity may significantly decrease the quality of patient–provider communication in VA primary care. By improving longitudinal continuity with the assigned PCP, while redesigning team-based roles, the PACT initiative has the potential to improve patient–provider communication.

     

From the Patient’s Perspective: The Impact of Training on Resident Physician’s Obesity Counseling

BACKGROUND

It is uncertain whether training improves physicians’ obesity counseling.

OBJECTIVE

To assess the impact of an obesity counseling curriculum for residents.

DESIGN

A non-randomized, wait-list/control design.

PARTICIPANTS

Twenty-three primary care internal medicine residents; 12 were assigned to the curriculum group, and 11 were assigned to the no-curriculum group. Over a 7-month period (1–8 months post-intervention) 163 of the residents’ obese patients were interviewed after their medical visits.

INTERVENTION

A 5-hour, multi-modal obesity counseling curriculum based on the 5As (Assess, Advise, Agree, Assist, Arrange) using didactics, role-playing, and standardized patients.

MAIN MEASURES

Patient-report of physicians’ use of the 5As was assessed using a structured interview survey. Main outcomes were whether obese patients were counseled about diet, exercise, or weight loss (rate of counseling) and the quality of counseling provided (percentage of 5As skills performed during the visit). Univariate statistics (t-tests) were used to compare the rate and quality of counseling in the two resident groups. Logistic and linear regression was used to isolate the impact of the curriculum after controlling for patient, physician, and visit characteristics.

KEY RESULTS

A large percentage of patients seen by both groups of residents received counseling about their weight, diet, and/or exercise (over 70%), but the quality of counseling was low in both the curriculum and no curriculum groups (mean 36.6% vs. 31.2% of 19 possible 5As counseling strategies, p?=?0.21). This difference was not significant. However, after controlling for patient, physician and visit characteristics, residents in the curriculum group appeared to provide significantly higher quality counseling than those in the control group (std β?=?0.18; R ² change?=?2.9%, P?<?0.05).

CONCLUSIONS

Residents who received an obesity counseling curriculum were not more likely to counsel obese patients than residents who did not. Training, however, is associated with higher quality of counseling when patient, physician, and visit characteristics are taken into account.     

The Effects of Primary Care Physician Visit Continuity on Patients’ Experiences with Care

Background Visit continuity is important to patients and valued by physicians. However, it is virtually impossible for primary care physicians (PCPs) to provide care during every paneled patient visit. It remains unclear whether PCP visit discontinuity can be planned in a way that is least disruptive to patients’ experiences with care. Objective This study aims to clarify whether visit continuity affects patients’ experiences with primary care equally for all patients. Design From January 2004 through March 2005, a large multispecialty practice in Massachusetts administered the Ambulatory Care Experience Survey (ACES) monthly to a random sample of patients visiting each of 145 PCPs. The analytic sample includes 14,835 patients with 2 or more primary care visits over the 6 months before being surveyed. Usual Provider Continuity (UPC), an administratively based measure of PCP visit continuity, was calculated for all respondents. Multilevel regression models that accounted for the clustering of patients within physicians modeled the relationship between UPC and each ACES measure. Interaction effects between UPC and gender, education, self-rated health, and PCP–patient relationship duration were tested. Results Physician–patient interaction quality, including physician communication, knowledge of the patient, health promotion support, and organizational access were more strongly influenced by visit continuity among respondents in early stages of a PCP–patient relationship (P < 0.01) and with worse self-rated health (P < 0.01). Conclusions Improvements in physician–patient relationship quality can be achieved by targeting visit continuity improvement efforts to patients who benefit most, particularly those in early stages of a PCP–patient relationship and/or perceive their health as poor.     

Internal Medicine Residents’ Perceptions of Team-Based Care and its Educational Value in the Continuity Clinic: A Qualitative Study

BACKGROUND

In order to teach residents how to work in interprofessional teams, educators in graduate medical education are implementing team-based care models in resident continuity clinics. However, little is known about the impact of interprofessional teams on residents’ education in the ambulatory setting.

OBJECTIVE

To identify factors affecting residents’ experience of team-based care within continuity clinics and the impact of these teams on residents’ education.

DESIGN

This was a qualitative study of focus groups with internal medicine residents.

PARTICIPANTS

Seventy-seven internal medicine residents at the University of California San Francisco at three continuity clinic sites participated in the study.

APPROACH

Qualitative interviews were audiotaped and transcribed. The authors used a general inductive approach with sensitizing concepts in four frames (structural, human resources, political and symbolic) to develop codes and identify themes.

KEY RESULTS

Residents believed that team-based care improves continuity and quality of care. Factors in four frames affected their ability to achieve these goals. Structural factors included communication through the electronic medical record, consistent schedules and regular team meetings. Human resources factors included the presence of stable teams and clear roles. Political and symbolic factors negatively impacted team-based care, and included low staffing ratios and a culture of ultimate resident responsibility, respectively. Regardless of the presence of these factors or resident perceptions of their teams, residents did not see the practice of interprofessional team-based care as intrinsically educational.

CONCLUSIONS

Residents’ experiences practicing team-based care are influenced by many principles described in the interprofessional teamwork literature, including understanding team members’ roles, good communication and sufficient staffing. However, these attributes are not correlated with residents’ perceptions of the educational value of team-based care. Including residents in interprofessional teams in their clinic may not be sufficient to teach residents how team-based care can enhance their overall learning and future practice.KEY WORDS: interprofessional collaboration, graduate medical education, qualitative research, primary care     

Use of a Registry-generated Audit,Feedback, and Patient Reminder Intervention in an Internal Medicine Resident Clinic—A Randomized Trial

BACKGROUND: Disease registries, audit and feedback, and clinical reminders have been reported to improve care processes. OBJECTIVE: To assess the effects of a registry-generated audit, feedback, and patient reminder intervention on diabetes care. DESIGN: Randomized controlled trial conducted in a resident continuity clinic during the 2003-2004 academic year. PARTICIPANTS: Seventy-eight categorical Internal Medicine residents caring for 483 diabetic patients participated. Residents randomized to the intervention (n = 39) received instruction on diabetes registry use; quarterly performance audit, feedback, and written reports identifying patients needing care; and had letters sent quarterly to patients needing hemoglobin A1c or cholesterol testing. Residents randomized to the control group (n = 39) received usual clinic education. MEASUREMENTS: Hemoglobin A1c and lipid monitoring, and the achievement of intermediate clinical outcomes (hemoglobin A1c <7.0%, LDL cholesterol <100 mg/dL, and blood pressure <130/85 mmHg) were assessed. RESULTS: Patients cared for by residents in the intervention group had higher adherence to guideline recommendations for hemoglobin A1c testing (61.5% vs 48.1%, p = .01) and LDL testing (75.8% vs 64.1%, p = .02). Intermediate clinical outcomes were not different between groups. CONCLUSIONS: Use of a registry-generated audit, feedback, and patient reminder intervention in a resident continuity clinic modestly improved diabetes care processes, but did not influence intermediate clinical outcomes.     

Differences in the Quality of the Patient–Physician Relationship Among Terminally Ill African-American and White Patients: Impact on Advance Care Planning and Treatment Preferences

BACKGROUND Little is known about the quality of the patient–physician relationship for terminally ill African Americans. OBJECTIVE To compare the quality of the patient–physician relationship between African-American and white patients and examine the extent to which relationship quality contributes to differences in advance care planning (ACP) and preferences for intensive life-sustaining treatment (LST). DESIGN Cross sectional survey of 803 terminally ill African-American and white patients. MEASUREMENTS Patient-reported quality of the patient–physician relationship (degree of trust, perceived respect, and joint decision making; skill in breaking bad news and listening; help in navigating the medical system), ACP, preferences for LST (cardiopulmonary resuscitation, major surgery, mechanical ventilation, and dialysis). RESULTS The quality of the patient–physician relationship was worse for African Americans than for white patients by all measures except trust. African Americans were less likely to have an ACP (adjusted relative risk [aRR] = 0.66, 95%CI = 0.52–0.84), and were more likely to have a preference for cardiopulmonary resuscitation and dialysis (aRR = 1.28, 95%CI = 1.03–1.58; aRR = 1.25, 95%CI = 1.07–1.47, respectively). Additional adjustment for the quality of the patient–physician relationship had no impact on the differences in ACP and treatment preferences. CONCLUSIONS Lower reported patient–physician relationship quality for African-American patients does not explain the observed differences between African Americans and whites in ACP and preferences for LST.     

The Role of Patient Activation on Patient–Provider Communication and Quality of Care for US and Foreign Born Latino Patients

BACKGROUND

Previous research has shown positive effects of patient activation on healthcare outcomes, but there is practically no information on the generalization of these findings for Latino patients. Little data are available on whether patient activation is associated with healthcare outcomes for Latino patients and whether activation varies by language proficiency and nativity status.

OBJECTIVE

We examined the levels of activation by characteristics of Latino patients (e.g. nativity, language, health status). We investigated whether patient activation relates to the quality of care received and enhanced doctor–patient communication for Latino patients.

DESIGN

We conducted analyses of 1,067 US born and foreign born Latinos who participated in the second wave of the PEW/RWJF Hispanic Healthcare Survey during 2008.

PARTICIPANTS

Participants were self-identified Latinos (18+) with a doctor visit, living in the contiguous United States who could be contacted by telephone.

RESULTS

US born Latinos had significantly (P?<?0.001) greater patient activation scores than foreign born Latinos (75 versus 70). Latinos classified as bilingual and those reporting excellent health evidenced higher mean activation scores as compared to Spanish-speaking Latinos and those reporting fair or poor health. After adjusting for demographics, health status, other language and service use factors, patient activation was strongly associated with self-reported quality of care and better doctor–patient communication among both US and foreign born Latino respondents.

CONCLUSIONS

Interventions that augment patient activation could increase quality of care and improved patient–provider communication, potentially reducing health care disparities for Latinos.

     

Impact of Non-HIV Related Comorbidities on Retention in HIV Medical Care: Does Retention Improve Over Time?

The purpose of this study was to understand how the presence of comorbid conditions affects retention in HIV medical care over time. A retrospective cohort design employing a medical chart review was conducted. A generalized linear mixed model was used to determine the predictors that affect retention over time. The mean follow-up for the study population was 5.75 years, and only 48.6 % achieved optimal retention. During the study period, 882 non-HIV related comorbidities were diagnosed in 610 (44.9 %) patients of whom, approximately 31 % had ≥2 comorbidities diagnosed. In the mixed model, the number of comorbidities diagnosed during the study period was associated with improved retention over time (odds ratio = 2.28; 95 % confidence interval = 1.83–2.71). Having a non-HIV related comorbid condition was associated with improved retention, while those patients who were ‘healthier’ had worse retention. More research is needed to identify factors that improve retention and to quantify the impact of these factors.     

Patient–Provider and Patient–Staff Racial Concordance and Perceptions of Mistreatment in the Health Care Setting

Objectives To determine what roles patient–provider and patient–staff racial concordance play on patients’ perceptions within the health care setting. Design, Setting, Participants Data from the Commonwealth Fund 2001 Quality of Care telephone survey. Analysis focused on the subsample of 6,066 adults who live in the continental United States and who reported having a regular provider or a usual source of care (n = 4,762). Measurements and Results We analyzed patients’ responses about perceptions of disrespect, unfair treatment because of race and language, and the belief that he/she would have received better treatment if he/she belonged to a different race. We compared these perceptions of mistreatment with provider and staff racial concordance, controlling for sociodemographic variables. Contrary to our hypothesis, Hispanics were more likely to report being treated with disrespect if in a concordant relationship with their provider than if in a nonconcordant one (odds ratio [OR] 2.42, P < .01). Asians were less likely to report being treated unfairly because of race if in racially concordant relationships with providers than if in nonconcordant ones (P < .05). Hispanics were also less likely to perceive unfair treatment because of language when in concordant relationships with staff as compared to nonconcordant relationships with staff (P < .05). Conclusions Patients’ perceptions of health care relationships may partially depend on racial concordance with providers and staff. The nature of the association between racial concordance and perceived disrespect varies by racial group, indicating that other race-specific factors may also need to be examined. The topics discussed in this paper were presented as an abstract at a conference for the Society of Academic Emergency Medicine, May 2006.     

Hurricane Katrina’s Impact on the Care of Survivors with Chronic Medical Conditions

BACKGROUND: Hurricane Katrina affected a population with significant levels of chronic disease. OBJECTIVE: The extent to which Hurricane Katrina disrupted treatments is not known but would be useful information for future disaster planning. PARTICIPANTS: 1,043 displaced and nondisplaced English-speaking Katrina survivors ages 18 and older who resided in affected areas before the hurricane. DESIGN AND SETTING: A geographically representative telephone survey conducted between January 19 and March 31, 2006. MEASUREMENTS AND MAIN RESULTS: The proportions of survivors with chronic illnesses in the 12 months before the hurricane and the extent to which those with chronic illnesses cut back or terminated treatments because of the disaster. Correlates and reasons given by survivors for disrupted treatment were identified. Most (73.9%) Katrina survivors had 1 or more chronic conditions in the year before the hurricane; of these, 20.6% cut back or terminated their treatment because of the disaster. Disruptions in treatment were significantly more common among the non-elderly, uninsured, socially isolated, those with housing needs, or for conditions remaining relatively asymptomatic but still dangerous if untreated. Frequent reasons for disrupted care included problems accessing physicians (41.1%), medications (32.5%), insurance/financial means (29.3%), transportation (23.2%), or competing demands on time (10.9%). CONCLUSIONS: Many Katrina survivors burdened by chronic disease had their treatments disrupted by the disaster. Future disaster management plans should anticipate and address such chronic care needs, with timely reestablishment of primary care services, access to medications, and means to address financial and structural barriers to treatment.     

Impact of HIV-1infection on survival in patients with haematological malignancies in Yaoundeé, Cameroon

The impact of HIV-1 infection on the survival of patients with haematological cancers in Yaoundeé, Cameroon, was examined. The prevalence of HIV-1 was 26.2% among 172 patients, predominantly lymphoid malignancies. At the time of analysis, 75% of patients had died giving an incidence rate of 0.05 deaths per year and a median of survival of 15 (6-27) months. However, the hazard ratio for HIV-infected patients to die was not statistically different from that of uninfected patients (1.3, 95% confidence interval: 0.9-2.0).     

Correlation of TSLP,IL-33, and CD4 + CD25 + FOXP3 + T regulatory (Treg) in pediatric asthma

Objective: Newly discovered cytokines TSLP and IL33 are being studied as important indicators of Th2 inflammation and their effect on Treg cells is likely to modulate immune response. We attempted to study TSLP and IL-33 and then correlated with Tregs in order to find possible biomarker in these patients. Methods: Sixty-five children (37 with asthma only and 28 with asthma and rhinitis) aged 6.4?±?3.2 years (patient group) and 15 healthy children aged 8.0?±?2.6 years (control group) were recruited in this study. In vitro analysis of TSLP and IL-33 was done in serum samples of 65 newly diagnosed children for allergic asthma and 15 healthy children using the sandwich ELISA method. The expression of Treg cells (CD4?+?CD25?+?FOXP3+) was analyzed by flow cytometry. Results: The mean TSLP in the patient group (592?±?68?pg/ml) was significantly higher than controls (215?±?45?pg/ml) (p?<?0.05). Alternatively, the expression of FOXP3?+?T reg cells was significantly lower in the patient group (52?±?36) compared with the controls (95.9?±?3.6) (p?=?0.003). IL-33 was also significantly higher (4044?±?413?pg/ml) in the patient group compared with the controls (3282?±?331.5?pg/ml) (p?=?0.0001). The expression of Treg cells was negatively correlated with the TSLP (r?=??0.23, p?=?0.07). Asthma control test (ACT) was also negatively correlated with TSLP in the patient group (r?=??0.14, p?>?0.05). Conclusion: Children with asthma show elevated serum levels of TSLP, which correlated negatively with asthma control test and Treg cells. TSLP may be used as a biomarker for inflammation in pediatric asthma patients.     

Patient–Physician Communication in the Primary Care Visits of African Americans and Whites with Depression

Background Little research investigates the role of patient–physician communication in understanding racial disparities in depression treatment. Objective The objective of this study was to compare patient–physician communication patterns for African-American and white patients who have high levels of depressive symptoms. Design, Setting, and Participants This is a cross-sectional study of primary care visits of 108 adult patients (46 white, 62 African American) who had depressive symptoms measured by the Medical Outcomes Study–Short Form (SF-12) Mental Component Summary Score and were receiving care from one of 54 physicians in urban community-based practices. Main Outcomes Communication behaviors, obtained from coding of audiotapes, and physician perceptions of patients’ physical and emotional health status and stress levels were measured by post-visit surveys. Results African-American patients had fewer years of education and reported poorer physical health than whites. There were no racial differences in the level of depressive symptoms. Depression communication occurred in only 34% of visits. The average number of depression-related statements was much lower in the visits of African-American than white patients (10.8 vs. 38.4 statements, p = .02). African-American patients also experienced visits with less rapport building (20.7 vs. 29.7 statements, p = .009). Physicians rated a higher percentage of African-American than white patients as being in poor or fair physical health (69% vs. 40%, p = .006), and even in visits where depression communication occurred, a lower percentage of African-American than white patients were considered by their physicians to have significant emotional distress (67% vs. 93%, p = .07). Conclusions This study reveals racial disparities in communication among primary care patients with high levels of depressive symptoms. Physician communication skills training programs that emphasize recognition and rapport building may help reduce racial disparities in depression care.     

Impact of Helicobacter pylori infection on histological changes in non-erosive reflux disease

AIM:The evidence for an association between Helicobacterpylori (H pylori) and gastroesophageal reflux disease,eitherin non-erosive (NERD) or erosive esophagitis (ERD) remainsuncertain.The available data on the histological changes inNERD and the effect on Hpyloriinfection on them are elusive.The aim of this study therefore was to prospectively evaluatethe histological findings and the impact of Hpyloriinfectionon a group of symptomatic patients with NERD.METHODS:Fifty consecutive patients were prospectivelyevaluated for symptoms compatible with GORD.In all cases,routine endoscopy and lugol directed biopsies were performedand assessed histologically in a blinded manner.RESULTS:The overall prevalence of Hpyloriinfection was70%.Twenty-nine patients out of 50 (58%) were NERDpatients.No statistical significance was observed betweenthe H pyloristatus and NERD.The remaining 21 (42%)were diagnosed as follows:13 (26%),6 (12%),2(4%) withesophagitis grade A,B and C respectively.A statisticallysignificant correlation was observed between the Hpylori and esophagitis grade A,as well as between Hpylori-andgrade B.Biopsies from 2 patients were not included becauseof insufficient materials.Histologically,a basal zone hyperplasiawas found in 47 (97.91%) patients,alterations of glycogencontent in 47 (97.91%),papillae elongation in 33 (68.75%),blood vessels dilatation in 35(72.91%),chronic inflammationin 21 (43.75%),infiltration with eosinophils,neutophils andT-lymphocytes in 4 (8.33%),6 (12.5%) and 39 (81.25%)respectively.No correlation was observed between theHpyloristatus and the histological parameters studied eitherin NERD or GERD.CONCLUSION:Histological assessment can not differentiatesymptomatic patients with erosive versus non-erosive refluxdisease.Moreover,Hpyloriinfection may not act as animportant factor in patients with NERD.     

UGT1A1 gene polymorphism： Impact on toxicity and efficacy of irinotecan-based regimens in metastatic colorectal cancer

AIM: To investigate the correlation between uridine diphosphate glucuronosyl transferase 1A1 ( UGT1A1) gene polymorphisms and irinotecan-associated side effects and parameters of drug efficacy in patients with metastatic colorectal cancer (mCRC) receiving a lowdose weekly irinotecan chemotherapeutic regimen.METHODS: Genotypes were retrospectively evaluated by gene scan analysis on the ABI 310 sequencer of the TATAA box in the promoter region of the UGT1A1 gene in blood samples from 105 patients who had received 1st line irinotecan-based chemotherapy for mCRC.RESULTS: The distribution of the genotypes was as follows: wild type genotype (WT) ( 6/6) 39.0%,heterozygous genotype ( 6/7) 49.5%, and homozygous genotype ( 7/7) 9.5%. The overall response rate (OR) was similar between patients carrying the ( 6/7, 7/7) or the WT genotype ( 6/6) (44.3% vs 43.2%, P = 0.75).Neither time to progression [(TTP) 8.1 vs 8.2 mo, P = 0.97] nor overall survival [(OS) 21.2 vs 18.9 mo, P = 0.73] differed significantly in patients who carried the ( 6/6) when compared to the ( 6/7, 7/7) genotype. No significant differences in toxicity were observed: Grade 3 and 4 delayed diarrhoea [( 6/7, 7/7) vs ( 6/6); 13.0% vs 6.2%, P =0.08], treatment delays [( 6/7, 7/7) vs ( 6/6); 25.1% vs 19.3%, P = 0.24] or dose reductions [( 6/7, 7/7) vs ( 6/6); 21.5% vs 27.2%, P = 0.07].CONCLUSION: This analysis demonstrates the nonsignificant influence of the UGT1A1 gene polymorphism on efficacy and rate of irinotecan-associated toxicity in mCRC patients receiving low-dose irinotecan based chemotherapy.