Response rates and associated factors after a multicomponent intervention in frail older adults with diabetes

BACKGROUND

Type 2 diabetes mellitus (T2DM) and frailty are associated with functional decline in older population.

OBJECTIVE

To explore the individual response to a multimodal intervention on functional performance.

DESIGN

A cluster-randomised multicentre clinical trial.

SETTING

Outpatients in hospital or primary care.

SUBJECTS

843 (77.83 years, 50.65% men) prefrail and frail individuals ≥70 years with T2DM.

METHODS

Participants were allocated to usual care group (UCG) or a multicomponent intervention group (IG): 16-week progressive resistance training, seven nutritional and diabetological educational sessions and achievement of glycated haemoglobin (7-8%) and blood pressure (<150 mmHg) targets. Functional performance was assessed with the Short Physical Performance Battery (SPPB) at 1 year. We used multivariate binomial and multinomial logistic regression models to explore the effect of the IG, and adherence on the outcomes studied, in several adjusted models.

RESULTS

53.7% in the IG versus 38.0% in the UCG improved by at least 1 point in their SPPB score [OR (95% CI): 2.07 (1.43, 2.98), P value <0.001]. Age, SPPB score and number of frailty criteria met decreased the probability of improving the SPPB score. Factors associated with worsening were pertaining to IG (decreased), age, SPPB score and the number of frailty criteria (increased). An adherence ≥84% was needed to achieve benefits, reaching the peak in the probability of improving SPPB when this was ≥85% [OR(95%CI): 2.38 (1.29, 4.79), P value 0.014].

CONCLUSIONS

Factors predicting the likelihood of improvement in a multimodal programme in pre-frail and frail older adults with diabetes are age, basal SPPB score, the number of frailty criteria and adherence.

Amino Acid Profiles in Older Adults with Frailty: Secondary Analysis from MetaboFrail and BIOSPHERE Studies

An altered amino acid metabolism has been described in frail older adults which may contribute to muscle loss and functional decline associated with frailty. In the present investigation, we compared circulating amino acid profiles of older adults with physical frailty and sarcopenia (PF&S, n = 94), frail/pre-frail older adults with type 2 diabetes mellitus (F-T2DM, n = 66), and robust non-diabetic controls (n = 40). Partial least squares discriminant analysis (PLS-DA) models were built to define the amino acid signatures associated with the different frailty phenotypes. PLS-DA allowed correct classification of participants with 78.2 ± 1.9% accuracy. Older adults with F-T2DM showed an amino acid profile characterized by higher levels of 3-methylhistidine, alanine, arginine, ethanolamine, and glutamic acid. PF&S and control participants were discriminated based on serum concentrations of aminoadipic acid, aspartate, citrulline, cystine, taurine, and tryptophan. These findings suggest that different types of frailty may be characterized by distinct metabolic perturbations. Amino acid profiling may therefore serve as a valuable tool for frailty biomarker discovery.

A Therapeutic Vibrating Insole Device for Postural Instability in Older People with Type 2 Diabetes: A Randomized Control Study

INTRODUCTION

Frail older people with diabetes often present with or develop walking impairments, in part due to lower-limb sensory-motor neuropathy. Several studies suggest a possible improvement of balance control using somatosensory stimulation. We undertook a novel randomized control trial, the aim of which was to observe whether use of this device for 1 month improves walking speed as measured in the 10-m fast walking speed test standardized to body size at month 1 (M1) (FWS). Secondary outcomes were the differences between intervention (VS) and control (C) in the 10-m normal walking speed test, step length, short physical performance battery, timed up and go test, and posturographic measures.

METHODS

Subjects were aged ≥ 70 years and had had type 2 diabetes for at least 2 years. The intervention (VS) at home consisted of 22-min daily vibrating sequences with noise intensity set at 90% of the tactile threshold for each foot. The same device was used in group C but noise was set to 0. Compliance was retrieved from the device.

RESULTS

Among 56 subjects, 27 were in the VS group and 29 in the C group; 35 subjects were frail, 15 were prefrail ,and 6 were non-frail. Bilateral neuropathy was present in 17 subjects. More than half of sessions were done in 36 subjects with no discernible difference according to intervention. At M1 there were no discernible differences in FWS between the groups [VS: 0.96 (0.53) cm s-1 cm-1, C: 0.94 (0.47) cm s-1 cm-1]. There were also no discernible differences in other outcomes, irrespective of the presence of bilateral neuropathy.

CONCLUSION

In a cohort of frail, prefrail, or non-frail older subjects with diabetes, a 1-month intervention using a vibrating insole device did not alter measures of walking speed and related measures. Larger studies with longer term and different stimulation protocols are required to test this hypothesis more fully.

Drug Induced Liver Injury in Geriatric Patients Detected by a Two-Hospital Prospective Pharmacovigilance Program: A Comprehensive Analysis Using the Roussel Uclaf Causality Assessment Method

Background/aim: A prospective evaluation of drug-induced liver injury (DILI) in two tertiary hospitals was conducted through a pharmacovigilance program from laboratory signals at hospital (PPLSH) to determine the principal characteristics of DILI in patients older than 65 years, a growing age group worldwide, which is underrepresented in the literature on DILI.

Methods: All DILI in patients older than 65 years detected by PPLSH in two hospitals were followed up for 8 years in the La Paz Hospital and 2 years in the Getafe Hospital. A descriptive analysis was conducted that determined the causality of DILI and suspected drugs, the incidence of DILI morbidities, DILI characteristics, laboratory patterns, evolution and outcomes.

Results: 458 DILI cases in 441 patients were identified, 31.0% resulting in hospitalisation and 69.0% developing during hospitalisation. The mean age was 76.61 years old (SD, 7.9), and 54.4% were women. The DILI incidence was 76.33/10,000 admissions (95%CI 60.78–95.13). Polypharmacy (taking >4 drugs) was present in 86.84% of patients, 39.68% of whom took >10 drugs. The hepatocellular phenotype was the most frequent type of DILI (53.29%), a higher proportion (65%) had a mild severity index, and, in 55.2% of the evaluated drugs the RUCAM indicated that the causal relationship was highly probable. The most frequently employed drugs were paracetamol (50-cases), amoxicillin-clavulanate (42-cases) and atorvastatin (37-cases). The incidence rate of in-hospital DILI per 10,000 DDDs was highest for piperacillin-tazobactam (66.96/10,000 DDDs). A higher risk of in-hospital DILI was associated with the therapeutic chemical group-J (antiinfectives for systemic use) (OR, 2.65; 95%CI 1.58–4.46) and group-N (central nervous system drugs) (OR, 2.33; 95%CI 1.26–4.31). The patients taking >4 medications presented higher maximum creatinine level (OR, 2.01; 95%CI 1.28–3.15), and the patients taking >10 medications had a higher use of group J drugs (OR, 2.08; 95%IC 1.31–3.32).

Conclusion: The incidence rate of DILI in the patients older than 65 years was higher than expected. DILI in elderly patients is mild, has a good outcome, has a hepatocellular pattern, develops during hospitalisation, and prolongs the hospital stay. Knowing the DILI incidence and explanatory factors will help improve the therapy of the elderly population.

Rapid Assessment at Hospital Admission of Mortality Risk From COVID-19: The Role of Functional Status

Objective

To evaluate the role of functional status along with other used clinical factors on the occurrence of death in patients hospitalized with COVID-19.

Design

Prospective cohort study.

Setting

Public university hospital (Madrid).

Participants and Methods

A total of 375 consecutive patients with COVID-19 infection, admitted to a Public University Hospital (Madrid) between March 1 and March 31, 2020, were included in the Prospective Cohort study. Death was the main outcome. The main variable was disability in activities of daily living (ADL) assessed with the Barthel Index. Covariates included sex, age, severity index (Quick Sequential Organ Failure Assessment, qSOFA), polypharmacy (≥5 drugs in the month before admission), and comorbidity (≥3 diseases). Multivariable logistic regression was used to identify risk factors for adverse outcomes. Estimated model coefficients served to calculate the expected probability of death for a selected combination of 5 variables: Barthel Index, sex, age, comorbidities, and severity index (qSOFA).

Results

Mean age was 66 years (standard deviation 15.33), and there were 207 (55%) men. Seventy-four patients died (19.8%). Mortality was associated with low Barthel Index (odds ratio per 5-point decrease 1.11, 95% confidence interval 1.03-1.20), male sex (0.23, 0.11-0.47), age (1.07, 1.03-1.10), and comorbidity (2.15, 1.08-4.30) but not with qSOFA (1.29, 0.87-1.93) or polypharmacy (1.54, 0.77-3.08). Calculated mortality risk ranged from 0 to 0.78.

Conclusions and Implications

Functional status predicts death in hospitalized patients with COVID-19. Combination of 5 variables allows to predict individual probability of death. These findings provide useful information for the decision-making process and management of patients.

Use of renin-angiotensin-aldosterone system inhibitors and risk of COVID-19 requiring admission to hospital: a case-population study

BACKGROUND

Concerns have been raised about the possibility that inhibitors of the renin-angiotensin-aldosterone system (RAAS) could predispose individuals to severe COVID-19; however, epidemiological evidence is lacking. We report the results of a case-population study done in Madrid, Spain, since the outbreak of COVID-19.

METHODS

In this case-population study, we consecutively selected patients aged 18 years or older with a PCR-confirmed diagnosis of COVID-19 requiring admission to hospital from seven hospitals in Madrid, who had been admitted between March 1 and March 24, 2020. As a reference group, we randomly sampled ten patients per case, individually matched for age, sex, region (ie, Madrid), and date of admission to hospital (month and day; index date), from Base de datos para la Investigación Farmacoepidemiológica en Atención Primaria (BIFAP), a Spanish primary health-care database, in its last available year (2018). We extracted information on comorbidities and prescriptions up to the month before index date (ie, current use) from electronic clinical records of both cases and controls. The outcome of interest was admission to hospital of patients with COVID-19. To minimise confounding by indication, the main analysis focused on assessing the association between COVID-19 requiring admission to hospital and use of RAAS inhibitors compared with use of other antihypertensive drugs. We calculated odds ratios (ORs) and 95% CIs, adjusted for age, sex, and cardiovascular comorbidities and risk factors, using conditional logistic regression. The protocol of the study was registered in the EU electronic Register of Post-Authorisation Studies, EUPAS34437.

FINDINGS

We collected data for 1139 cases and 11 390 population controls. Among cases, 444 (39·0%) were female and the mean age was 69·1 years (SD 15·4), and despite being matched on sex and age, a significantly higher proportion of cases had pre-existing cardiovascular disease (OR 1·98, 95% CI 1·62-2·41) and risk factors (1·46, 1·23-1·73) than did controls. Compared with users of other antihypertensive drugs, users of RAAS inhibitors had an adjusted OR for COVID-19 requiring admission to hospital of 0·94 (95% CI 0·77-1·15). No increased risk was observed with either angiotensin-converting enzyme inhibitors (adjusted OR 0·80, 0·64-1·00) or angiotensin-receptor blockers (1·10, 0·88-1·37). Sex, age, and background cardiovascular risk did not modify the adjusted OR between use of RAAS inhibitors and COVID-19 requiring admission to hospital, whereas a decreased risk of COVID-19 requiring admission to hospital was found among patients with diabetes who were users of RAAS inhibitors (adjusted OR 0·53, 95% CI 0·34-0·80). The adjusted ORs were similar across severity degrees of COVID-19.

INTERPRETATION

RAAS inhibitors do not increase the risk of COVID-19 requiring admission to hospital, including fatal cases and those admitted to intensive care units, and should not be discontinued to prevent a severe case of COVID-19.

FUNDING

Instituto de Salud Carlos III.

Economic evaluation of a multimodal intervention in pre-frail and frail older people with diabetes mellitus: the MID-FRAIL project

Background: The aim of this study was to estimate the incremental cost-utility ratio (ICUR) of a multi-modal intervention in frail and pre-frail subjects aged ≥70 years with type-2 diabetes versus usual care group focused on quality adjusted life years (QALYs) in different European countries. Methods: The MID-FRAIL study was a cluster randomized multicentre trial conducted in seven European countries. A cost-utility analysis was carried out based on this study, conducted from the perspective of the health care system with a time horizon of one year. Univariate and probabilistic analysis were carried out to test the robustness of the results. Results: The cost estimation showed the offsetting health effect of the intervention program on total health care costs. The mean annual health care costs were 25% higher among patients in usual care. The mean incremental QALY gained per patient by the intervention group were 0.053 QALY compared with usual care practice. Conclusions: The MID-FRAIL intervention program showed to be the dominant option in comparison with usual care practice. It saved costs to the health care system and achieved worthwhile health gains. This finding should encourage its implementation, at least, in the trial participant countries.

Identification of a Circulating Amino Acid Signature in Frail Older Persons with Type 2 Diabetes Mellitus: Results from the Metabofrail Study

Diabetes and frailty are highly prevalent conditions that impact the health status of older adults. Perturbations in protein/amino acid metabolism are associated with both functional impairment and type 2 diabetes mellitus (T2DM). In the present study, we compared the concentrations of a panel of circulating 37 amino acids and derivatives between frail/pre-frail older adults with T2DM and robust non-diabetic controls. Sixty-six functionally impaired older persons aged 70+ with T2DM and 30 age and sex-matched controls were included in the analysis. We applied a partial least squares-discriminant analysis (PLS-DA)-based analytical strategy to characterize the metabotype of study participants. The optimal complexity of the PLS-DA model was found to be two latent variables. The proportion of correct classification was 94.1 ± 1.9% for frail/pre-frail persons with T2DM and 100% for control participants. Functionally impaired older persons with T2DM showed higher levels of 3-methyl histidine, alanine, arginine, glutamic acid, ethanolamine sarcosine, and tryptophan. Control participants had higher levels of ornithine and taurine. These findings indicate that a specific profile of amino acids and derivatives characterizes pre-frail/frail older persons with T2DM. The dissection of these pathways may provide novel insights into the metabolic perturbations involved in the disabling cascade in older persons with T2DM.

Effectiveness of a multimodal intervention in functionally impaired older people with type 2 diabetes mellitus

BACKGROUND

Type 2 diabetes, a highly prevalent chronic disease, is associated with increasing frailty and functional decline in older people. We aimed to evaluate the effectiveness of a multimodal intervention on functional performance in frail and pre-frail participants aged ≥70 years with type 2 diabetes mellitus.

METHODS

The MID-Frail study was a cluster-randomized multicenter clinical trial conducted in 74 trial sites across seven European countries. The trial recruited 964 participants who were aged >70 years [mean age in intervention group, 78.4 (SD 5.6) years, 49.2% male and 77.6 (SD 5.29) years, 52.4% male in usual care group], with type diabetes mellitus and determined to be frail or pre-frail using Fried's frailty phenotype. Participants were allocated by trial site to follow either usual care (UCG) or intervention procedures (IG). Intervention group participants received a multimodal intervention composed of (i) an individualized and progressive resistance exercise programme for 16 weeks; (ii) a structured diabetes and nutritional educational programme over seven sessions; and (iii) Investigator-linked training to ensure optimal diabetes care. Short Physical Performance Battery (SPPB) scores were used to assess change in functional performance at 12 months between the groups. An analysis of the cost-effectiveness of the intervention was undertaken using the incremental cost-effectiveness ratio (ICER). Secondary outcomes included mortality, hospitalization, institutionalization, quality of life, burden on caregivers, the frequency and severity of hypoglycaemia episodes, and the cost-effectiveness of the intervention.

RESULTS

After 12 months, IG participants had mean SPPB scores 0.85 points higher than those in the UCG (95% CI, 0.44 to 1.26, P < 0.0001). Dropouts were higher in frail participants and in the intervention group, but significant differences in SPPB between treatment groups remained consistent after sensitivity analysis. Estimates suggest a mean saving following intervention of 428.02 EUR (2016) per patient per year, with ICER analysis indicating a consistent benefit of the described health care intervention over usual care. No statistically significant differences between groups were detected in any of the other secondary outcomes.

CONCLUSIONS

We have demonstrated that a 12 month structured multimodal intervention programme across several clinical settings in different European countries leads to a clinically relevant and cost-effective improvement in the functional status of older frail and pre-frail participants with type 2 diabetes mellitus.

Diabetes and frailty

PURPOSE OF REVIEW

Disability and its preceding condition, frailty, are outstanding issues for achieving healthy aging. Diabetes is a very prevalent chronic disease among older patients that favours frailty status. This review will analyse the relationship between diabetes and frailty in the elderly and summarize the current strategies to improve physical function in diabetic older patients.

RECENT FINDINGS

We have analyzed the current knowledge providing insight on the relationship between frailty and diabetes in older people. Epidemiological evidences and potential mechanisms connecting diabetes with frailty in the aging process have been examined. Finally, the strategies to reduce frailty in aged population with diabetes were discussed.

SUMMARY

Current evidence reveals the high prevalence of diabetes in frail older patients, producing an additional impairment of physical performance in this population. Insulin resistance seems to contribute to this clinical manifestation which is related to the impact of diabetes on skeletal muscle function, on vascular function, and on the hormonal milieu. Exercise, nutritional and educational interventions, and less strict glycaemic control appear as the most effective strategies to reduce frailty in diabetic older people.

Significant HLA class I type associations with aromatic antiepileptic drug (AED)-induced SJS/TEN are different from those found for the same AED-induced DRESS in the Spanish population

Aromatic antiepileptic drugs (AEDs) are among the drugs most frequently involved in severe cutaneous adverse reactions (SCARs), such as Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and drug reactions with eosinophilia and systemic symptoms (DRESS). This study investigated the associations between the genetic polymorphisms of HLA class-I and AED-induced SCARs in the Spanish population. HLA class-I genotypes were determined in AED (phenytoin[PHT],lamotrigine[LTG],carbamazepine[CBZ],phenobarbital[PB])-induced SJS/TEN (n=15) or DRESS (n=12) cases included in the Spanish SCAR registry, PIELenRed. There were 3 control groups: (A)tolerant to a single AED, (B)tolerant to any AED, and (C)Spanish population controls. For SJS/TEN, concomitant HLA-A*02:01/Cw15:02 alleles were significantly associated with PHT-cases compared to control groups B and C [(B)odds ratio(OR):14.75, p=0.009;(C)OR:27.50, p<0.001], and were close to significance with respect to control group A (p=0.060). The genotype frequency of the HLA-B*38:01 was significantly associated with PHT-LTG-cases compared with the 3 groups of controls [(A)OR:12.86, p=0.012;(B)OR:13.81; p=0.002;(C)OR:14.35, p<0.001], and with LTG-cases [(A)OR:147.00, p=0.001;(B)OR:115.00, p<0.001;(C)OR:124.70, p<0.001]. We found the HLA-B*15:02 allele in a Spanish Romani patient with a CBZ-case. The HLA-A*11:01 was significantly associated with CBZ-cases [(A)OR:63.89, p=0.002;(B)OR:36.33, p=0.005;(C)OR:28.29, p=0.007]. For DRESS, the HLA-A*24:02 genotype frequency was statistically significant in the PHT-LTG-cases [(A)OR:22.56, p=0.003;(B)OR:23.50. p=0.001; (C)OR:33.25, p<0.001], and in the LTG-cases [(A),OR:49.00, p=0.015;(B)OR:27.77, p=0.005; (C)OR:34.53, p=0.002]. HLA-A*31:01 was significantly associated with the CBZ-cases [(A)OR:22.00, p=0.047;(B)OR:29.50, p=0.033;(C)OR:35.14, p=0.006]. In conclusion, we identified several significant genetic risk factors for the first time in the Spanish Caucasian population: HLA-A*02:01/Cw*15:02 combination as a risk factor for PHT-induced SJS/TEN, HLA-B*38:01 for LTG- and PHT- induced SJS/TEN, HLA-A*11:01 for CBZ-induced SJS/TEN, and HLA-A*24:02 for LTG- and PHT- induced DRESS. The strong association between HLA*31:01 and CBZ-DRESS in Europeans was confirmed in this study.

The HLA-B*15:02 allele in a Spanish Romani patient with carbamazepine-induced Stevens-Johnson syndrome

The HLA-B*15:02 allele is a risk factor for carbamazepine (CBZ)-induced Stevens-Johnson syndrome/toxic epidermal necrolysis in populations where the allele is prevalent. Han Chinese and Thai patients are advised to take a genetic test before introducing CBZ. Such testing is not recommended for patients of European descent. We report the case of a Spanish Romani patient who developed Stevens-Johnson syndrome upon treatment with CBZ. In vitro assays confirmed CBZ as the culprit drug. HLA typing showed that the patient carried the HLA-B*15:02 allele. A public database search revealed that 2% of Spanish Romani people likely carry the risk variant HLA-B*15:02 and therefore may be included in the population to be tested prior to beginning treatment with CBZ.

Interventional tools to improve medication adherence: review of literature

Medication adherence and persistence is recognized as a worldwide public health problem, particularly important in the management of chronic diseases. Nonadherence to medical plans affects every level of the population, but particularly older adults due to the high number of coexisting diseases they are affected by and the consequent polypharmacy. Chronic disease management requires a continuous psychological adaptation and behavioral reorganization. In literature, many interventions to improve medication adherence have been described for different clinical conditions, however, most interventions seem to fail in their aims. Moreover, most interventions associated with adherence improvements are not associated with improvements in other outcomes. Indeed, in the last decades, the degree of nonadherence remained unchanged. In this work, we review the most frequent interventions employed to increase the degree of medication adherence, the measured outcomes, and the improvements achieved, as well as the main limitations of the available studies on adherence, with a particular focus on older persons.

Pharmaceutical interventions for frailty and sarcopenia

Frailty has emerged as one of the most relevant clinical syndromes in older patients. This term relates to the loss of functional reserve that can occur in some older people following exposure to one or more low-intensity stressors placing them at high risk for developing a number of adverse outcomes such as disability, falls, hospitalization and death. Frailty is the outcome of two combined effects: the ageing process and other superimposed injuries like chronic disease or, indeed, psychological and social stressors. The mechanisms leading to frailty typically involve several systems: mainly hormones, oxidative stress, inflammation, immunity, and vascular system. One of the most outstanding pillars of the frailty syndrome is the loss of muscle quantity and function, referred to as sarcopenia. The main bulk of experimental pharmacological interventions addressing the clinical problem of frailty have been focused on the use of hormones, as replacement therapy in subjects with low or normal circulating basal levels of the hormone. Results have been disappointing, except for the case of testosterone that have shown some benefits. The effectiveness of other potential therapeutic interventions (antioxidants, anti-inflammatory agents, nutritional supplements) appears to be limited or has not been explored in detail until now. In conclusion, there is an available path to prevent the development of disability in older people through the treatment of frailty, its main risk factor. Aditional research and further experimental testing will help to identify new targets and help to make this journey successful.

An evaluation of the effectiveness of a multi-modal intervention in frail and pre-frail older people with type 2 diabetes--the MID-Frail study: study protocol for a randomised controlled trial

BACKGROUND

Diabetes, a highly prevalent, chronic disease, is associated with increasing frailty and functional decline in older people, with concomitant personal, social, and public health implications. We describe the rationale and methods of the multi-modal intervention in diabetes in frailty (MID-Frail) study.

METHODS/DESIGN

The MID-Frail study is an open, randomised, multicentre study, with random allocation by clusters (each trial site) to a usual care group or an intervention group. A total of 1,718 subjects will be randomised with each site enrolling on average 14 or 15 subjects. The primary objective of the study is to evaluate, in comparison with usual clinical practice, the effectiveness of a multi-modal intervention (specific clinical targets, education, diet, and resistance training exercise) in frail and pre-frail subjects aged ≥70 years with type 2 diabetes in terms of the difference in function 2 years post-randomisation. Difference in function will be measured by changes in a summary ordinal score on the short physical performance battery (SPPB) of at least one point. Secondary outcomes include daily activities, economic evaluation, and quality of life.

DISCUSSION

The MID-Frail study will provide evidence on the clinical, functional, social, and economic impact of a multi-modal approach in frail and pre-frail older people with type 2 diabetes.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01654341.

Acceptability and characteristics of 124 human bioequivalence studies with active substances classified according to the Biopharmaceutic Classification System

AIM

The aim of this study was to evaluate the acceptability of 124 bioequivalence (BE) studies with 80 active substances categorized according to the Biopharmaceutics Classification System (BCS) in order to establish if there were different probabilities of proving BE between the different BCS classes.

METHODS

We evaluated the differences between pharmaceutical products with active substances from different BCS classes in terms of acceptability, number of subjects in the study (n), the point estimates, and intra- and inter-subject coefficients of variation data from BE studies with generic products.

RESULTS

Out of 124 BE studies 89 (71.77%) were performed with pharmaceutical products containing active substances classified by the BCS. In all BCS classes there were non-bioequivalent pharmaceutical products: 4 out of 26 (15.38%) in class 1, 14 out of 28 (50%) in class 2, 3 out of 22 (13.63%) in class 3 and 1 out of 13 (7.69%) in class 4. When we removed those pharmaceutical products in which intra-subject variability was higher than predicted (2 in class 1 active substances, 9 in class 2 and 2 in class 3) there were still non-BE pharmaceutical products in classes 1, 2 and 3.

CONCLUSIONS

Comparisons between pharmaceutical products with active substances from the four BCS classes have not allowed us to define differential characteristics of each class in terms of n, inter and intra-subject variability for C(max) or AUC. Despite the usually employed test dissolution methodology proposed as quality control, pharmaceutical products with active substances from the four classes of BCS showed non-BE studies.

The importance of sample size, log-mean ratios, and intrasubject variability in the acceptance criteria of 108 bioequivalence studies

PURPOSE

Fulfilling bioequivalence criteria with highly variable drugs is difficult. The aim of this study was to compare the importance of sample size, intrasubject variability, and the point estimate of test and reference formulations with regard to meeting bioequivalence (BE) criteria [maximum observed plasma concentration (C(max)) and area under the concentration-time curve (AUC)].

METHODS

We compared 137 pairs of data from BE studies with a conventional number of subjects, approximately 31-32 volunteers, developed in the last 10 years.

RESULTS

The third part of the studies failed to demonstrate BE, in part due to an unacceptable difference between the mean ratios (T/R) (18) but also due to high variability with small differences between formulations (17). Increasing the number of subjects is hard to justify, and expanding the confidence interval (CI) was insufficient for the most highly variable drugs.

CONCLUSIONS

Therefore, for low-variable drugs, the difference between formulations was the cornerstone of the fulfillment of BE criteria, but for highly variable drugs, the intrasubject coefficient of variability (ICV) was decisive. Our proposal is that for highly variable drugs that fall outside BE 90% CI limits could result in BE in the absence of formulation effect and maximal differences between formulations below 20%.