Symptoms, burden, and unmet needs of patients living with exocrine pancreatic insufficiency: a narrative review of the patient experience.

Exocrine pancreatic insufficiency (EPI) stems from a deficiency of functional pancreatic enzymes with consequent maldigestion and malnutrition. EPI shares clinical symptoms and manifestations with other disorders and is a considerable burden to individuals affected. In this narrative review, we analyzed the literature to identify relevant publications on living with EPI with the scope of individuating evidence gaps, including those related to symptoms, health-related quality of life (HRQoL), emotional functioning, disease burden, presence of comorbidities, and the use of pancreatic enzyme replacement therapy (PERT). Abdominal pain emerged as one of the most prominent symptoms. HRQoL was affected in EPI, but no articles examined emotional functioning. Comorbidities reported involved other pancreatic disorders, diabetes, gastrointestinal disorders, sarcopenia and osteopenia, cardiovascular disorders, bacterial overgrowth, and nutritional deficiencies. PERT was found to be effective in improving EPI symptoms and was well tolerated by most individuals. Our review revealed a dearth of literature evidence on patients' experience with EPI, such as emotional functioning and disease burden. We also revealed that studies on long-term effects of PERT are missing, as are studies that would help advance the understanding of the disease and its progression, risk/mitigating factors, and comorbidities. Future studies should address these identified gaps.

Metformin for the prevention of clozapine-induced weight gain: A retrospective naturalistic cohort study.

OBJECTIVE: Clozapine is presently the sole antipsychotic with an indication for treatment-resistant Schizophrenia, but is associated with significant weight gain and other metabolic aberrations. This retrospective chart review aimed to evaluate the effectiveness of adjunctive metformin in preventing clozapine-induced weight gain. METHODS: We conducted a retrospective chart review of patients newly initiated on clozapine at the Centre for Addiction and Mental Health in Canada, from November 2014 to April 2021. Our primary outcome was body weight at 6 and 12 months after clozapine initiation. Other metabolic parameters served as secondary outcomes. RESULTS: Among 396 patients (males: 71.5%, mean age: 42.8 years) initiated on clozapine, 69 were on metformin or prescribed it ≤3 months after clozapine initiation. The clozapine+metformin group demonstrated less weight gain compared with the clozapine-only group at 6 months (clozapine+metformin: -0.15 kg [SE = 1.08] vs. clozapine-only: 2.99 kg, SE = 0.54) and 12 months after clozapine initiation (clozapine+metformin: -0.67 kg, SE = 1.22 vs. clozapine-only: 4.72 kg, SE = 0.67). Adaptive changes were also observed for fasting glucose (F = 3.10, p = 0.046) and triglycerides (F = 8.56, p < 0.001) in the clozapine+metformin group compared with clozapine only. CONCLUSION: In this large retrospective naturalistic cohort study, co-prescription of clozapine and metformin was associated with less weight gain and related metabolic dysfunction at 6 and 12 months after initiation versus clozapine alone. These findings provide evidence for the effectiveness of metformin in preventing clozapine-induced weight gain; larger randomized controlled trials are needed to confirm these results.

Improving diversity in study participation: Patient perspectives on barriers, racial differences and the role of communities.

INTRODUCTION: The lack of racial/ethnic diversity in research potentially limits the generalizability of findings to a broader population, highlighting the need for greater diversity and inclusion in clinical research. Qualitative research (i.e., focus groups) was conducted to identify (i) the potential motivators and barriers to study participation across different races and ethnicities; (ii) preferred delivery of education and information to support healthcare decision-making and the role of the community. METHODS: Patient focus groups were conducted with 26 participants from the sponsor's Patient Engagement Research Councils selected through subjective sampling. Recruitment prioritized adequate representation across different race/ethnic groups. Participation was voluntary and participants underwent a confidential interview process before selection. Narrative analysis was used to identify themes and draw insights from interactions. Experienced research specialists identified emerging concepts, and these were tested against new observations. The frequency of each concept was examined to understand its importance. RESULTS: Based on self-selected race/ethnicity, participants were divided into five focus groups (Groups: African American/Black: 2; Hispanic/Latino, Asian American, and white: 1 each) and were asked to share their experiences/opinions regarding the stated objectives. Barriers to study participation included: limited awareness of opportunities to participate in research, fears about changes in standard therapy, breaking cultural norms/stigma, religion-related concerns and mistrust of clinical research. Participants identified the importance of transparency by pharmaceutical companies and other entities to build trust and partnership and cited key roles that communities can play. The perceptions of the African American group regarding diversity/inclusion in research studies appeared to be different from other groups; a lack of trust in healthcare providers, concerns about historical instances of research abuse and the importance of prayer were cited. CONCLUSION: This study provided insights into barriers to study participation, and also highlighted the need for pharmaceutical companies and other entities to authentically engage in strategies that build trust within communities to enhance recruitment among diverse populations. PATIENT OR PUBLIC CONTRIBUTION: The data collected in the present study was provided by the participants in the focus groups.

Clozapine-Related Myocarditis and Rechallenge: A Case Series and Clinical Review.

PURPOSE/BACKGROUND: That clozapine is the only agent with an indication for treatment-resistant schizophrenia presents real challenges if clozapine-related myocarditis (CIM) occurs. Clinicians have chosen to rechallenge with a second trial of clozapine in the face of CIM. However, there is very limited literature of this topic. METHODS/PROCEDURES: Three cases who underwent clozapine rechallenge after CIM are reviewed and discussed in the context of existing literature and current recommendations. FINDINGS/RESULTS: We present 3 young male patients with schizophrenia and schizoaffective disorder who developed CIM during a first clozapine trial, stopped treatment, and subsequently underwent a second clozapine trial. In all cases, the rechallenge was discontinued owing to suspected CIM. A review of the literature includes reports of both successful and unsuccessful clozapine rechallenges after CIM and suggests certain risk factors. Clozapine rechallenge after CIM may be undertaken, as now occurs on occasion with agranulocytosis, although rates of success may be lower. Any such undertaking calls for education, careful monitoring, cautious titration, and a multidisciplinary approach. The balance of risk versus benefits must be considered, and strategies may include a drug holiday, more frequent monitoring upon reinitiation, and slower titration. IMPLICATIONS/CONCLUSIONS: Pressure to undertake a rechallenge reflects clozapine's unique role in treatment-resistant schizophrenia and absence of other comparable options. However, it is not without risk, and more research is needed to understand those at increased risk, as well as established strategies that diminish this.

Positive symptoms are associated with clinicians' global impression in treatment-resistant schizophrenia.

Previous investigations on the relationship between global rating measures and symptoms have not considered the additional role of functioning. In this naturalistic study, we examined the relationship between symptom domains and functioning on Clinical Global Impression scales for severity (CGI-S) and improvement (CGI-I) in a sample of patients with schizophrenia assessed to be treatment resistant. Participants were patients with a diagnosis of schizophrenia or schizoaffective disorder who failed 2 prior antipsychotic trials and were considered candidates for clozapine. They were assessed on the 18-item Brief Psychiatric rating Scale (BPRS), Social Occupational Functioning Assessment Scale (SOFAS), and CGI-S at baseline. A subset of patients was followed up at 6 weeks after initiation of clozapine and assessed on the CGI-I. The independent effects of symptom domains and functioning on the CGI scales were examined via multivariate regression models. Brief Psychiatric rating Scale positive factor (P < 0.001) and SOFAS (P < 0.001) scores were significant determinants of CGI-S at baseline. Multivariate models suggested that relative change measures had a better fit for the CGI-I compared to absolute change measures (R = 0.72 vs R = 0.61, respectively). Improvements in BPRS positive (P < 0.001) and affect (P = 0.002) factors and SOFAS (P = 0.030) scores were significant determinants of CGI-I. Ratings of 1 and 2 on the CGI-I corresponded to a mean relative change in the BPRS total of 65% and 41%, respectively. Positive symptoms were a key determinant of clinicians' impression of severity and improvement in this study. Although psychosocial functioning played a large part in determining severity, it was not as significant in the assessment of improvement.

The Effect of Clozapine on Hematological Indices: A 1-Year Follow-Up Study.

Clozapine is the antipsychotic of choice for treatment-resistant schizophrenia and is linked to a need for mandatory hematological monitoring. Besides agranulocytosis, other hematological aberrations have resulted in premature termination in some cases. Considering clozapine's role in immunomodulation, we proceeded to investigate the impact of clozapine on the following 3 main hematological cell lines: red blood cells, platelets, white blood cells (WBCs), and its differential counts. Data were extracted from patients initiated on clozapine between January 2009 and December 2010 at a single hospital. Patients with a preclozapine complete blood count, who were receiving clozapine during the 1-year follow-up period, were included in the present investigation. Counts of red blood cells, platelets, WBC, and its differential including neutrophils, lymphocytes, monocytes, eosinophils, and basophils were extracted and trajectories plotted. One hundred one patients were included in this study and 66 remained on clozapine at the end of 1 year. There was a synchronized but transient increase in WBC, neutrophils, monocytes, eosinophils, basophils, and platelets beginning as early as the first week of clozapine treatment. There were no cases of agranulocytosis reported in this sample, and five developed neutropenia. A spike in neutrophils immediately preceded the onset of neutropenia in three of the five. The cumulative incidence rates were 48.9% for neutrophilia, 5.9% for eosinophilia, and 3% each for thrombocytosis and thrombocytopenia. Early hematological aberrations are visible across a range of cell lines, primarily of the myeloid lineage. These disturbances are transient and are probably related to clozapine's immunomodulatory properties. We do not suggest discontinuing clozapine as a consequence of the observed aberrations.

Safety of BEN guidelines in clozapine treatment: A Canadian perspective.

OBJECTIVE: Unidentified benign ethnic neutropenia (BEN) has been recognized as a factor contributing to clozapine underutilization and discontinuation. Guidelines were implemented to accommodate BEN in Canada, and our main objective was to evaluate clozapine's safety in a sample of Canadian psychiatric patients with BEN. METHOD: A retrospective chart review was conducted at the Centre for Addiction and Mental Health, Toronto, Canada. Through the clozapine clinic registry, participants were identified who (i) received clozapine using the approved BEN guidelines for hematological monitoring, and (ii) had at least one complete blood count pre- and post-clozapine initiation. RESULTS: Our sample population was comprised of 41 BEN patients who were African-Caribbean (49 %), African (34 %), African-North American (12 %), Middle Eastern (2 %), and Indian-Caribbean (2 %). There was a significant reduction in hematological alerts for these patients while monitored under BEN guidelines (p < 0.001). The mean within-patient ANC value was not significantly different one year after clozapine initiation compared to the pre-clozapine baseline (p = 0.069). None of the patients discontinued clozapine for hematological reasons. CONCLUSIONS: Findings demonstrated that patients monitored under the modified hematological guidelines for BEN can be safely treated with clozapine. These findings have important clinical ramifications as increased implementation of BEN guidelines may allow for broader use of clozapine.

Acute effects of single-dose olanzapine on metabolic, endocrine, and inflammatory markers in healthy controls.

Atypical antipsychotics may "directly" influence glucose homeostasis, increasing risk of type 2 diabetes independently of changes in adiposity. Animal models suggest direct effects after even a single dose of certain atypical antipsychotics on glucose dysregulation. Here, we investigated effects of a single-dose olanzapine (OLA) on glucose metabolism in healthy volunteers, thereby minimizing confounding effects of the illness of schizophrenia and adiposity. In a randomized double-blind crossover design, 15 subjects were administered 10 mg of OLA or placebo at 7:00 A.M. on separate study dates. A frequently sampled intravenous glucose tolerance test was initiated 4.25 hours later to assess changes in glucose homeostasis, including an index of insulin sensitivity, disposition index, glucose effectiveness, and acute insulin response to glucose. We also examined effects on cortisol, prolactin, fasting free fatty acids (FFAs), insulin-mediated suppression of FFAs, and adipocytokines (leptin, adiponectin, C-reactive protein, interleukin 6, and tumor necrosis factor α). Complete data for both visits were analyzed for 12 subjects. Olanzapine treatment significantly decreased glucose effectiveness (P = 0.041) and raised fasting glucose over 4.25 hours (P = 0.03) as compared to placebo. Olanzapine was associated with lower serum cortisol (P = 0.003), lower fasting FFA (P = 0.042), and increased prolactin levels (P < 0.0001). We therefore suggest that a single dose of OLA may invoke early changes in some parameters of glucose and lipid metabolism, as well as endocrine indices.

Surgical management of diabetic foot infections and amputations.

The incidence of diabetes with severe foot infections (eg, necrotizing fasciitis, gas gangrene, ascending cellulitis, infection with systemic toxicity or metabolic instability) has risen significantly during the past decade. Foot infections are a major cause of hospitalization and subsequent lower extremity amputation among patients with diabetes mellitus who have a history of a preexisting ulceration. Surgical management often is required to address severe diabetic foot infections because they can be limb- or life-threatening. Critical limb ischemia, neuropathy, and an immunocompromised host, which often are associated with diabetic foot infections, complicate treatment and are associated with a poorer prognosis.

Plastic surgery reconstruction of the diabetic foot.

Soft tissue reconstruction of the diabetic foot is a challenge for the perioperative team. Primary closure may not be an option and secondary healing may not be reliable. Therefore, surgery is vital and should be coordinated among a well-functioning multidisciplinary team that specializes in caring for patients with diabetes mellitus. Team members must have expertise in reconstructive surgery to ensure adequate wound healing. This article emphasizes the appropriate timing and staging of surgery, discusses the most common plastic surgery techniques, and underscores the importance of a team approach in the management of diabetic foot wounds.

Surgical treatment of Charcot neuropathy.

Charcot neuroarthropathy, a chronic progressive destruction of joint integrity, is believed to result from a disturbance in pain and proprioceptive sensation. It is most commonly treated in patients with uncontrolled diabetes mellitus and dense peripheral neuropathy. Prevention, early diagnosis, and early treatment are key to a patient's successful outcome. Educating the patient is paramount to avoid further complications and subsequent amputations. This article describes the pathophysiology, staging, surgical treatment, and natural course of Charcot neuroarthropathy.

Quantifying intraindividual variations in plasma clozapine levels: a population pharmacokinetic approach.

OBJECTIVE: Clozapine has strong recommendations for therapeutic drug monitoring. While factors that influence interindividual variation in plasma clozapine levels have been extensively reported, intraindividual variation remains poorly studied. We employed a population pharmacokinetic approach to assess intraindividual variations in plasma levels of both clozapine and N-desmethylclozapine, as well as the impact of smoking on this variability. METHODS: Patients who were initiated on clozapine from January 2009 to December 2010 and who provided at least 2 plasma samples were included in this study. The observed concentrations of clozapine and N-desmethylclozapine were applied in a Bayesian pharmacokinetic modeling approach by using a previously published pharmacokinetic model from an independent sample to compute a predicted concentration. The predicted concentrations of clozapine and N-desmethylclozapine were then compared with the observed concentrations in the form of a ratio: predicted-to-observed concentration ratio (Cpred/Cobs). The coefficient of variation of the Cpred/Cobs ratios was taken as a measure of intraindividual variation. RESULTS: A total of 723 plasma levels from 61 patients were included in this analysis. The coefficient of variation of Cpred/Cobs ratios for clozapine and N-desmethylclozapine were 29.8% (SD = 17.2%) and 27.4% (SD = 16.4%), respectively. Though values were higher, smoking did not have a significant effect on coefficients of variation of clozapine (33.5% vs 26.3%, P = .184) or N-desmethylclozapine (30.7% vs 24.2%, P = .100). CONCLUSIONS: Clinicians need to be aware of intraindividual variability and not assume that plasma levels are static. If plasma levels are used to guide dosing of clozapine, serial measurements rather than a single level might be necessary to make an informed clinical decision. The clinical implications of intraindividual variability in plasma clozapine levels need further study.

Clozapine and anemia: a 2-year follow-up study.

OBJECTIVE: Clozapine's association with agranulocytosis led to the implementation of stringent and mandatory hematologic monitoring guidelines in most countries. Although other hematologic aberrations such as eosinophilia and neutropenia have been previously described, clozapine's impact on the erythroid lineage has not been studied. There is a suspicion that a higher rate of anemia is observed in patients receiving clozapine; therefore, we hypothesized that there would be a higher rate of anemia in patients receiving clozapine therapy. METHOD: All individuals initiated on clozapine at our center from 2009 to 2010 were recruited. Information on age, gender, medical comorbidities, and smoking status was extracted from the medical records. Data from complete blood counts over a 2-year follow-up period were extracted, with anemia defined as a hemoglobin value below 120 g/L for women and 130 g/L for men. Time to anemia event was calculated and Cox regression was employed to identify predictors of anemia. RESULTS: We found a high incidence of anemia in the first 2 years following clozapine initiation; of the 94 individuals (68 men, 26 women) recruited, 23 (24.5%) developed anemia. Higher baseline hemoglobin level (hazard ratio [HR] = 0.86, P = .002) and smoking status (HR = 0.21, P = .021) were identified as significant protective factors against anemia in men but not in women (HR = 0.92, P = .184, and HR = 0.52, P = .467 for baseline hemoglobin and smoking, respectively). CONCLUSIONS: Although smoking appears to lower the risk of anemia, we believe this is due to smoking's up-regulation of hemoglobin levels. Further studies are warranted in light of the present findings; for example, we cannot exclude the possibility that anemia was an epiphenomenon, characterizing instead a population with severe mental illness.

Mean platelet volume in schizophrenia unaltered after 1year of clozapine exposure.

This study investigated the MPV of patients with major psychoses before and after 1year of clozapine exposure. Data were obtained from chart reviews of patients who were initiated on clozapine at the Centre of Addiction and Mental Health (CAMH) in Toronto. 100 patients were eligible for this study; 65 remained on clozapine after 1year. Prior to clozapine initiation, MPV was 10.79±0.91fL and there was no difference in MPV after 1year of clozapine exposure (p=0.777). We found high MPV in patients with schizophrenia and related psychoses, which was unaltered after 1year of clozapine treatment.

Relationship between clinical improvement and functional gains with clozapine in schizophrenia.

Impairment in psychosocial functioning is a key feature in schizophrenia, but few studies have examined the relationship between improvements in symptoms and functioning. We examined the relationship between change in symptoms and change in functioning in a group of patients with treatment-resistant schizophrenia after 6 and 12 weeks of clozapine treatment. Participants were assessed prior to clozapine and again at 6 and 12-week on the 18-item Brief Psychiatric Rating Scale (BPRS) and the Social and Occupational Functioning Scale (SOFAS). Change scores in BPRS and SOFAS at 6 and 12-week post-clozapine were calculated and the direct relationship was assessed via regression models. Forty-three participants were included in this study; age of sample was 42.1 ± 12.7 years, with 31 (72.1%) male participants. At baseline, the mean BPRS total and SOFAS scores were 46.98 ± 12.86 and 33.07 ± 10.79, respectively. There were significant improvements in BPRS total and SOFAS scores at 6 weeks, but no significant differences between 6 and 12-week assessments. There was no significant change in negative symptoms at both follow-up assessments. At 6-week, change in symptoms was not correlated with change in functioning and while the relationship between change in symptoms and functioning was stronger at 12 weeks, none of the BPRS factors emerged as a significant predictor. The present study found that lower baseline SOFAS score was the most robust predictor for improvements in SOFAS at 6 and 12-weeks. There appears to be a "ceiling" for functional improvements on clozapine, but follow-up studies are needed to examine functional gains beyond 12 weeks.

Clozapine and therapeutic drug monitoring: is there sufficient evidence for an upper threshold?

RATIONALE: Clozapine levels are advocated in the monitoring of patients on this drug and have now been used for a number of years. A safety-related threshold has also been proposed, as well as therapeutic lower and upper thresholds. While there has been reasonable consensus regarding a lower therapeutic threshold, this is not the case for the upper thresholds. OBJECTIVES: Our aim was to review available evidence related to upper thresholds. METHODS: We carried out an electronic search of different databases and a manual search of articles between 1960 and 2011, cross-referencing the following terms with clozapine-interactions, monitoring, pharmacokinetics, plasma levels, serum levels, and toxicity. RESULTS: Sixty-nine articles met our search criteria and these could be divided into reviews (11), studies (24), and case reports (35). Study quality was evaluated, and none met criteria for a prospective, randomized controlled trial specifically addressing higher plasma levels, e.g., >500 ng/ml. Case reports emphasize in particular the impact of interactions, e.g., antidepressants and smoking. There is clear evidence indicating a dose-related increased risk of seizures, at least to 500-600 mg/day, but a lack of data to suggest such a relationship between plasma levels, dose, and side effects linked to safety, e.g., seizures, myocarditis, and agranulocytosis. The very limited evidence addressing an upper threshold related to clinical response suggests a "ceiling effect" in the range of 600-838 ng/ml. CONCLUSIONS: It appears that the current safety-related threshold is not supported by evidence. There may be an upper threshold for clinical response, beyond which chance of response falls off, although further studies are warranted.

Determining rates of hepatitis C in a clozapine treated cohort.

OBJECTIVE: To determine the prevalence rates of hepatitis C in patients with schizophrenia and schizoaffective disorder being treated with clozapine. METHODS: Clozapine-treated outpatients and inpatients were recruited from the Centre for Addiction and Mental Health Schizophrenia Program in Toronto, Canada. All subjects had liver function tests, and positive HCV status was defined as a positive qualitative HCV RNA assay. Subjects completed a self-report questionnaire assessing HCV risk factors, past history of liver disease, previous diagnosis of human immunodeficiency virus (HIV), past hepatitis B virus (HBV) infection and current alcohol use. RESULTS: 110 subjects participated in the study and the HCV prevalence rate (antibody and viremia-positive) was 2.7%, compared to a 0.8% prevalence rate in Canada. All study subjects had established housing, none reported a history of HIV, and only one patient had a history of HBV infection. A total of 9% drank two or more drinks on a typical day drinking and 7% endorsed having six or more drinks on one occasion at least monthly. Two of 3HCV-viremia positive subjects had HCV risk factors, specifically intravenous drug use and intranasal cocaine use. There was no difference between HCV infected and HCV negative subjects on liver function tests. CONCLUSIONS: Our study demonstrates elevated rates of HCV in clozapine-treated patients compared to the general population in Canada and are congruent with reports from United States centres. Our study highlights the importance of homelessness and patterns of high-risk behaviour when interpreting HCV prevalence rates in this sub-population of patients and should be explored in future studies.