Storylines of family medicine VIII: clinical approaches

Storylines of Family Medicine is a 12-part series of thematically linked mini-essays with accompanying illustrations that explore the many dimensions of family medicine as interpreted by individual family physicians and medical educators in the USA and elsewhere around the world. In 'VIII: clinical approaches', authors address the following themes: 'Evaluation, diagnosis and management I-toward a working diagnosis', 'Evaluation, diagnosis and management II-process steps', 'Interweaving integrative medicine and family medicine', 'Halfway-the art of clinical judgment', 'Seamless integration in family medicine-team-based care', 'Technology-uncovering stories from noise' and 'Caring for patients with multiple long-term conditions'. May readers recognise in these essays the uniqueness of a family medicine approach to care.

Impact of individual, household, and area characteristics on health and social care outcomes for people with multimorbidity: Protocol for a multilevel analysis

BACKGROUND

Multimorbidity is one of the greatest challenges facing health and social care systems globally. It is associated with high rates of health service use, adverse healthcare events, and premature death. Despite its importance, little is known about the effects of contextual determinants such as household and area characteristics on health and care outcomes for people with multimorbidity. This study protocol presents a plan for the examination of associations between individual, household, and area characteristics with important health and social care outcomes.

METHODS

The study will use a cross-section of data from the SAIL Databank on 01 January 2019 and include all people alive and registered with a Welsh GP. The cohort will be stratified according to the presence or absence of multimorbidity, defined as two or more long-term conditions. Multilevel models will be used to examine covariates measured for individuals, households, and areas to account for social processes operating at different levels. The intra-class correlation coefficient will be calculated to determine the strength of association at each level of the hierarchy. Model outcomes will be any emergency department attendance, emergency hospital or care home admission, or mortality, within the study follow-up period.

DISCUSSION

Household and area characteristics might act as protective or risk factors for health and care outcomes for people with multimorbidity, in which case results of the analyses can be used to guide clinical and policy responses for effective targeting of limited resources.

Trajectories in chronic disease accrual and mortality across the lifespan in Wales, UK (2005-2019), by area deprivation profile: linked electronic health records cohort study on 965,905 individuals

Background

Understanding and quantifying the differences in disease development in different socioeconomic groups of people across the lifespan is important for planning healthcare and preventive services. The study aimed to measure chronic disease accrual, and examine the differences in time to individual morbidities, multimorbidity, and mortality between socioeconomic groups in Wales, UK.

Methods

Population-wide electronic linked cohort study, following Welsh residents for up to 20 years (2000-2019). Chronic disease diagnoses were obtained from general practice and hospitalisation records using the CALIBER disease phenotype register. Multi-state models were used to examine trajectories of accrual of 132 diseases and mortality, adjusted for sex, age and area-level deprivation. Restricted mean survival time was calculated to measure time spent free of chronic disease(s) or mortality between socioeconomic groups.

Findings

In total, 965,905 individuals aged 5-104 were included, from a possible 2.9 m individuals following a 5-year clearance period, with an average follow-up of 13.2 years (12.7 million person-years). Some 673,189 (69.7%) individuals developed at least one chronic disease or died within the study period. From ages 10 years upwards, the individuals living in the most deprived areas consistently experienced reduced time between health states, demonstrating accelerated transitions to first and subsequent morbidities and death compared to their demographic equivalent living in the least deprived areas. The largest difference were observed in 10 and 20 year old males developing multimorbidity (-0.45 years (99% CI: -0.45, -0.44)) and in 70 year old males dying after developing multimorbidity (-1.98 years (99% CI: -2.01, -1.95)).

Interpretation

This study adds to the existing literature on health inequalities by demonstrating that individuals living in more deprived areas consistently experience accelerated time to diagnosis of chronic disease and death across all ages, accounting for competing risks.

Funding

UK Medical Research Council, Health Data Research UK, and Administrative Data Research Wales.

Impact of data source choice on multimorbidity measurement: a comparison study of 2.3 million individuals in the Welsh National Health Service

BACKGROUND

Measurement of multimorbidity in research is variable, including the choice of the data source used to ascertain conditions. We compared the estimated prevalence of multimorbidity and associations with mortality using different data sources.

METHODS

A cross-sectional study of SAIL Databank data including 2,340,027 individuals of all ages living in Wales on 01 January 2019. Comparison of prevalence of multimorbidity and constituent 47 conditions using data from primary care (PC), hospital inpatient (HI), and linked PC-HI data sources and examination of associations between condition count and 12-month mortality.

RESULTS

Using linked PC-HI compared with only HI data, multimorbidity was more prevalent (32.2% versus 16.5%), and the population of people identified as having multimorbidity was younger (mean age 62.5 versus 66.8 years) and included more women (54.2% versus 52.6%). Individuals with multimorbidity in both PC and HI data had stronger associations with mortality than those with multimorbidity only in HI data (adjusted odds ratio 8.34 [95% CI 8.02-8.68] versus 6.95 (95%CI 6.79-7.12] in people with ≥ 4 conditions). The prevalence of conditions identified using only PC versus only HI data was significantly higher for 37/47 and significantly lower for 10/47: the highest PC/HI ratio was for depression (14.2 [95% CI 14.1-14.4]) and the lowest for aneurysm (0.51 [95% CI 0.5-0.5]). Agreement in ascertainment of conditions between the two data sources varied considerably, being slight for five (kappa < 0.20), fair for 12 (kappa 0.21-0.40), moderate for 16 (kappa 0.41-0.60), and substantial for 12 (kappa 0.61-0.80) conditions, and by body system was lowest for mental and behavioural disorders. The percentage agreement, individuals with a condition identified in both PC and HI data, was lowest in anxiety (4.6%) and highest in coronary artery disease (62.9%).

CONCLUSIONS

The use of single data sources may underestimate prevalence when measuring multimorbidity and many important conditions (especially mental and behavioural disorders). Caution should be used when interpreting findings of research examining individual and multiple long-term conditions using single data sources. Where available, researchers using electronic health data should link primary care and hospital inpatient data to generate more robust evidence to support evidence-based healthcare planning decisions for people with multimorbidity.

The impact of varying the number and selection of conditions on estimated multimorbidity prevalence: A cross-sectional study using a large, primary care population dataset

BACKGROUND

Multimorbidity prevalence rates vary considerably depending on the conditions considered in the morbidity count, but there is no standardised approach to the number or selection of conditions to include.

METHODS AND FINDINGS

We conducted a cross-sectional study using English primary care data for 1,168,260 participants who were all people alive and permanently registered with 149 included general practices. Outcome measures of the study were prevalence estimates of multimorbidity (defined as ≥2 conditions) when varying the number and selection of conditions considered for 80 conditions. Included conditions featured in ≥1 of the 9 published lists of conditions examined in the study and/or phenotyping algorithms in the Health Data Research UK (HDR-UK) Phenotype Library. First, multimorbidity prevalence was calculated when considering the individually most common 2 conditions, 3 conditions, etc., up to 80 conditions. Second, prevalence was calculated using 9 condition-lists from published studies. Analyses were stratified by dependent variables age, socioeconomic position, and sex. Prevalence when only the 2 commonest conditions were considered was 4.6% (95% CI [4.6, 4.6] p < 0.001), rising to 29.5% (95% CI [29.5, 29.6] p < 0.001) considering the 10 commonest, 35.2% (95% CI [35.1, 35.3] p < 0.001) considering the 20 commonest, and 40.5% (95% CI [40.4, 40.6] p < 0.001) when considering all 80 conditions. The threshold number of conditions at which multimorbidity prevalence was >99% of that measured when considering all 80 conditions was 52 for the whole population but was lower in older people (29 in >80 years) and higher in younger people (71 in 0- to 9-year-olds). Nine published condition-lists were examined; these were either recommended for measuring multimorbidity, used in previous highly cited studies of multimorbidity prevalence, or widely applied measures of "comorbidity." Multimorbidity prevalence using these lists varied from 11.1% to 36.4%. A limitation of the study is that conditions were not always replicated using the same ascertainment rules as previous studies to improve comparability across condition-lists, but this highlights further variability in prevalence estimates across studies.

CONCLUSIONS

In this study, we observed that varying the number and selection of conditions results in very large differences in multimorbidity prevalence, and different numbers of conditions are needed to reach ceiling rates of multimorbidity prevalence in certain groups of people. These findings imply that there is a need for a standardised approach to defining multimorbidity, and to facilitate this, researchers can use existing condition-lists associated with highest multimorbidity prevalence.

Age, sex, and socioeconomic differences in multimorbidity measured in four ways: UK primary care cross-sectional analysis

BACKGROUND

Multimorbidity poses major challenges to healthcare systems worldwide. Definitions with cut-offs in excess of ≥2 long-term conditions (LTCs) might better capture populations with complexity but are not standardised.

AIM

To examine variation in prevalence using different definitions of multimorbidity.

DESIGN AND SETTING

Cross-sectional study of 1 168 620 people in England.

METHOD

Comparison of multimorbidity (MM) prevalence using four definitions: MM2+ (≥2 LTCs), MM3+ (≥3 LTCs), MM3+ from 3+ (≥3 LTCs from ≥3 International Classification of Diseases, 10th revision chapters), and mental-physical MM (≥2 LTCs where ≥1 mental health LTC and ≥1 physical health LTC are recorded). Logistic regression was used to examine patient characteristics associated with multimorbidity under all four definitions.

RESULTS

MM2+ was most common (40.4%) followed by MM3+ (27.5%), MM3+ from 3+ (22.6%), and mental-physical MM (18.9%). MM2+, MM3+, and MM3+ from 3+ were strongly associated with oldest age (adjusted odds ratio [aOR] 58.09, 95% confidence interval [CI] = 56.13 to 60.14; aOR 77.69, 95% CI = 75.33 to 80.12; and aOR 102.06, 95% CI = 98.61 to 105.65; respectively), but mental-physical MM was much less strongly associated (aOR 4.32, 95% CI = 4.21 to 4.43). People in the most deprived decile had equivalent rates of multimorbidity at a younger age than those in the least deprived decile. This was most marked in mental-physical MM at 40-45 years younger, followed by MM2+ at 15-20 years younger, and MM3+ and MM3+ from 3+ at 10-15 years younger. Females had higher prevalence of multimorbidity under all definitions, which was most marked for mental-physical MM.

CONCLUSION

Estimated prevalence of multimorbidity depends on the definition used, and associations with age, sex, and socioeconomic position vary between definitions. Applicable multimorbidity research requires consistency of definitions across studies.

Interventions in primary and community care to reduce urgent paediatric hospital admissions: systematic review

BACKGROUND

There has been a rise in urgent paediatric hospital admissions and interventions to address this are required.

OBJECTIVE

To systemically review the literature describing community (or non-hospital)-based interventions designed to reduce emergency department (ED) visits or urgent hospital admissions.

DATA SOURCES

MEDLINE, Embase, OVIS SP, PsycINFO, Science Citation Index Expanded/ISI Web of Science (1981-present), the Cochrane Library database and the Database of Abstracts of Reviews of Effectiveness.

STUDY ELIGIBILITY CRITERIA

Randomised controlled trials (RCTs) and before-and-after studies.

PARTICIPANTS

Individuals aged <16 years.

STUDY APPRAISAL AND SYNTHESIS METHODS

Papers were independently reviewed by two researchers. Data extraction and the Critical Appraisals Skills Programme checklist was completed (for risk of bias assessment).

RESULTS

Seven studies were identified. Three studies were RCTs, three were a comparison between non-randomised groups and one was a before-and-after study. Interventions were reconfiguration of staff roles (two papers), telemedicine (three papers), pathways of urgent care (one paper) and point-of-care testing (one paper). Reconfiguration of staff roles resulted in reduction in ED visits in one study (with a commensurate increase in general practitioner visits) but increased hospital admissions from ED in a second. Telemedicine was associated with a reduction in children's admissions in one study and reduced ED admissions in two further studies. Interventions with pathways of care and point-of-care testing did not impact either ED visits or urgent admissions.

CONCLUSIONS AND IMPLICATIONS

New out-of-hospital models of urgent care for children need to be introduced and evaluated without delay.

PROSPERO REGISTRATION NUMBER

CRD42021274374.

Dietary supplementation of clinically utilized PI3K p110α inhibitor extends the lifespan of male and female mice

Diminished insulin and insulin-like growth factor-1 signaling extends the lifespan of invertebrates^1-4; however, whether it is a feasible longevity target in mammals is less clear^5-12. Clinically utilized therapeutics that target this pathway, such as small-molecule inhibitors of phosphoinositide 3-kinase p110α (PI3Ki), provide a translatable approach to studying the impact of these pathways on aging. Here, we provide evidence that dietary supplementation with the PI3Ki alpelisib from middle age extends the median and maximal lifespan of mice, an effect that was more pronounced in females. While long-term PI3Ki treatment was well tolerated and led to greater strength and balance, negative impacts on common human aging markers, including reductions in bone mass and mild hyperglycemia, were also evident. These results suggest that while pharmacological suppression of insulin receptor (IR)/insulin-like growth factor receptor (IGFR) targets could represent a promising approach to delaying some aspects of aging, caution should be taken in translation to humans.

Half a century of the inverse care law: A comparison of general practitioner job satisfaction and patient satisfaction in deprived and affluent areas of Scotland

BACKGROUND AND AIMS

The 'inverse care law', first described in 1971, results from a mismatch of healthcare need and healthcare supply in deprived areas. GPs in such areas struggle to cope with the high levels of demand resulting in shorter consultations and poorer patient outcomes. We compare recent national GP and patient satisfaction data to investigate the ongoing existence of this disparity in Scotland.

METHODS AND RESULTS

Secondary analysis of cross-sectional national surveys (2017/2018) on upper and lower deprivation quintiles. GP measures; job satisfaction, job stressors, positive and negative job attributes. Patient measures; percentage positive responses per practice on survey questions on access and consultation quality. GPs in high deprivation areas reported lower job satisfaction and positive job attributes, and higher job stressors and negative job attributes compared with GPs in low deprivation areas. Patients living in high deprivation areas reported lower satisfaction with access and consultation quality than patients in low deprivation areas. These differences in GP and patient satisfaction persisted after adjusting for confounding variables.

CONCLUSIONS

Lower GP work satisfaction in deprived areas was mirrored by lower patient satisfaction. These findings add to the evidence that the inverse care law persists in Scotland, over 50 years after it was first described.

Multimorbidity and comorbidity patterns in the English National Health Service

In an observational population-based study including nearly four million participants, Kuan et al. examined frequencies of common combinations of diseases and identified non-random disease associations in people of all ages and multiple ethnicities.

Household and area determinants of emergency department attendance and hospitalisation in people with multimorbidity: a systematic review

OBJECTIVES

Multimorbidity is one of the greatest challenges facing healthcare internationally. Emergency department (ED) attendance and hospitalisation rates are higher in people with multimorbidity, but most research focuses on associations with individual characteristics, ignoring household or area mediators of service use.

DESIGN

Systematic review reported using the synthesis without meta-analysis framework.

DATA SOURCES

Twelve electronic databases (1 January 2000-21 September 2021): MEDLINE/OVID, Embase, Global Health, PsycINFO, ASSIA, CAB Abstracts, Science Citation Index Expanded/ISI Web of Science, Scopus, Cumulative Index to Nursing and Allied Health Literature, Sociological Abstracts, the Cochrane Library, and OpenGrey.

ELIGIBILITY CRITERIA

Adults aged ≥16 years, with multimorbidity. Exposure(s) were household and/or area determinants of health. Outcomes were ED attendance and/or hospitalisation. The literature search was limited to publications in English.

DATA EXTRACTION AND SYNTHESIS

Independent double screening of titles and abstracts to select relevant full-text studies. Methodological quality was assessed using an adaptation of the Newcastle-Ottawa Quality Assessment Scale tool. Given high study heterogeneity, narrative synthesis was performed.

RESULTS

After deduplication, 10 721 titles and abstracts were screened, and 142 full-text articles were reviewed, of which 10 were eligible for inclusion. In people with multimorbidity, household food insecurity was associated with hospitalisation (OR 1.58 (95% CI 1.06 to 2.36) in concordant multimorbidity). People with multimorbidity living in the most versus least deprived areas attended ED more frequently (8.9% (95% CI 8.6 to 9.1) in most versus 6.3% (95% CI 6.1 to 6.6) in least), had higher rates of hospitalisation (26% in most versus 22% in least), and higher probability of hospitalisation (6.4% (95% CI 5.8 to 7.2) in most versus 4.2% (95% CI 3.8 to 4.7) in least). There was non-conclusive evidence that household income is associated with ED attendance and hospitalisation. No statistically significant relationships were found between marital status, living with others with multimorbidity, or rurality with ED attendance or hospitalisation.

CONCLUSIONS

There is some evidence that household and area contexts mediate associations of multimorbidity with ED attendance and hospitalisation, but firm conclusions are constrained by the small number of studies published and study design heterogeneity. Further research is required on large population samples using robust analytical methods.

PROSPERO REGISTRATION NUMBER

CRD42021283515.

Variation in multimorbidity prevalence by number of long-term conditions counted: primary care population cross-sectional study

ObjectivesMultimorbidity poses a major challenge to healthcare systems worldwide, but there is no standardised approach to measuring multimorbidity. Existing studies include a median of 17 (IQR 11-23, range 2-285) long-term conditions (LTCs), making it difficult to compare or replicate research, particularly research examining the prevalence of multimorbidity. ApproachIn this cross-sectional study of 1,168,620 people from the Clinical Practice Research Datalink, we extracted data on 99 LTCs defined by validated code-sets, including all conditions recommended as core by a recent Delphi study. We examined how the prevalence of multimorbidity defined as ≥2 LTCs, varied when including different numbers of LTCs in the measure. We calculated multimorbidity prevalence when including only the two most prevalent LTCs, repeating the calculation for 3,4,5, through to 99 LTCs, added in order of descending prevalence. Results were stratified by age, sex, and socioeconomic status (SES). ResultsUsing only the two most prevalent LTCs, 16.8% of people had multimorbidity, compared to 39.3% for 10 LTCs, 42.0% for 25 LTCs, 42.5% for 50 LTCs, 42.6% for 75 LTCs, and 42.6% for all 99 LTCs. Whole population prevalence was essentially stable once 46+ LTCs were included (estimated prevalence change from adding any additional LTC <0.01%) and this was true in all age strata. The absolute difference in estimated prevalence using 99 versus using two LTCs was smallest in younger people (0.3% difference aged 0-4yrs), large in older people (20.4% ≥90yrs), largest in middle age (37.0% 55-59yrs), and was socially patterned, being lowest for people living in the most affluent areas (SES decile 1= 24.2%) and highest in the most deprived areas (SES decile 10=28.9%). ConclusionEstimates of multimorbidity prevalence vary markedly depending on how many LTCs are counted, with absolute differences in estimated prevalence largest for people in middle-age and with lowest SES. Further research is needed to support implementation of a uniform approach to defining how many conditions to include in multimorbidity measures.

Interventions to reduce acute paediatric hospital admissions: a systematic review

BACKGROUND

Admission rates are rising despite no change to burden of illness, and interventions to reduce unscheduled admission to hospital safely may be justified.

OBJECTIVE

To systematically examine admission prevention strategies and report long-term follow-up of admission prevention initiatives.

DATA SOURCES

MEDLINE, Embase, OVID SP, PsychINFO, Science Citation Index Expanded/ISI Web of Science, The Cochrane Library from inception to time of writing. Reference lists were hand searched.

STUDY ELIGIBILITY CRITERIA

Randomised controlled trials and before-and-after studies.

PARTICIPANTS

Individuals aged <18 years.

STUDY APPRAISAL AND SYNTHESIS METHODS

Studies were independently screened by two reviewers with final screening by a third. Data extraction and the Critical Appraisals Skills Programme checklist completion (for risk of bias assessment) were performed by one reviewer and checked by a second.

RESULTS

Twenty-eight studies were included of whom 24 were before-and-after studies and 4 were studies comparing outcomes between non-randomised groups. Interventions included referral pathways, staff reconfiguration, new healthcare facilities and telemedicine. The strongest evidence for admission prevention was seen in asthma-specific referral pathways (n=6) showing 34% (95% CI 28 to 39) reduction, but with evidence of publication bias. Other pathways showed inconsistent results or were insufficient for wider interpretation. Staffing reconfiguration showed reduced admissions in two studies, and shorter length of stay in one. Short stay admission units reduced admissions in three studies.

CONCLUSIONS AND IMPLICATIONS

There is little robust evidence to support interventions aimed at preventing paediatric admissions and further research is needed.

Deriving a Standardised Recommended Respiratory Disease Codelist Repository for Future Research

Background

Electronic health record (EHR) databases provide rich, longitudinal data on interactions with healthcare providers and can be used to advance research into respiratory conditions. However, since these data are primarily collected to support health care delivery, clinical coding can be inconsistent, resulting in inherent challenges in using these data for research purposes.

Methods

We systematically searched existing international literature and UK code repositories to find respiratory disease codelists for asthma from January 2018, and chronic obstructive pulmonary disease and respiratory tract infections from January 2020, based on prior searches. Medline searches using key terms provided in article lists. Full-text articles, supplementary files, and reference lists were examined for codelists, and codelists repositories were searched. A reproducible methodology for codelists creation was developed with recommended lists for each disease created based on multidisciplinary expert opinion and previously published literature.

Results

Medline searches returned 1126 asthma articles, 70 COPD articles, and 90 respiratory infection articles, with 3%, 22% and 5% including codelists, respectively. Repository searching returned 12 asthma, 23 COPD, and 64 respiratory infection codelists. We have systematically compiled respiratory disease codelists and from these derived recommended lists for use by researchers to find the most up-to-date and relevant respiratory disease codelists that can be tailored to individual research questions.

Conclusion

Few published papers include codelists, and where published diverse codelists were used, even when answering similar research questions. Whilst some advances have been made, greater consistency and transparency across studies using routine data to study respiratory diseases are needed.

Variation in referrals from primary care to scheduled paediatric services in North and East Scotland -a cross-sectional study

BACKGROUND

Factors contributing to decisions to refer children for scheduled appointments at medical paediatric outpatient clinics are not well understood. Our aim was to describe practice-level characteristics associated with referrals to general paediatric clinics.

METHODS

In this cross-sectional study the setting was general practices in three health boards in Scotland, NHS Grampian, NHS Highland and NHS Tayside The outcome was average annual number of referrals per 1000 children between 2011 and 2017. Univariate and multivariate analyses related the outcome to practice characteristics. For each practice the following characteristics were determined: distance from hospital; area deprivation; number of children registered; presence of ≥ 1 general practitioner with a child health interest and practice ownership.

RESULTS

There were 62 practices in NHS Grampian, 63 in NHS Highland, and 65 in NHS Tayside; representative annual number of referrals to paediatric clinics per capita were 22, 34, and 35/1000 respectively. In the multivariate model, the number of referrals was inversely related to number of children in the practice (0.8 % fall per 1000 children [95 % confidence interval, CI, 0.5, 1.1]) and was higher from practices in the more deprived areas by a mean 55 % [95 % CI 9, 121] compared to less deprived areas. The number of referrals from a practice rose by 0.91 % [95 % CI 0.86, 0.97] for each additional partner in the practice.

CONCLUSION

Some practice-level characteristics were related to the standardised number of referrals, and associations differed between regions.

Indirect effects of the COVID-19 pandemic on paediatric healthcare use and severe disease: a retrospective national cohort study

OBJECTIVES

To determine the indirect consequences of the COVID-19 pandemic on paediatric healthcare utilisation and severe disease at a national level following lockdown on 23 March 2020.

DESIGN

National retrospective cohort study.

SETTING

Emergency childhood primary and secondary care providers across Scotland; two national paediatric intensive care units (PICUs); statutory death records.

PARTICIPANTS

273 455 unscheduled primary care attendances; 462 437 emergency department attendances; 54 076 emergency hospital admissions; 413 PICU unplanned emergency admissions requiring invasive mechanical ventilation; and 415 deaths during the lockdown study period and equivalent dates in previous years.

MAIN OUTCOME MEASURES

Rates of emergency care consultations, attendances and admissions; clinical severity scores on presentation to PICU; rates and causes of childhood death. For all data sets, rates during the lockdown period were compared with mean or aggregated rates for the equivalent dates in 2016-2019.

RESULTS

The rates of emergency presentations to primary and secondary care fell during lockdown in comparison to previous years. Emergency PICU admissions for children requiring invasive mechanical ventilation also fell as a proportion of cases for the entire population, with an OR of 0.52 for likelihood of admission during lockdown (95% CI 0.37 to 0.73), compared with the equivalent period in previous years. Clinical severity scores did not suggest children were presenting with more advanced disease. The greatest reduction in PICU admissions was for diseases of the respiratory system; those for injury, poisoning or other external causes were equivalent to previous years. Mortality during lockdown did not change significantly compared with 2016-2019.

CONCLUSIONS

National lockdown led to a reduction in paediatric emergency care utilisation, without associated evidence of severe harm.

Cardiovascular safety profile of IPI-504 (retaspimycin hydrochloride), a novel Hsp90 inhibitor: Results from two independent phase I trials in patients with advanced cancer

e14539

Background: Heat shock protein 90 (Hsp90) is a protein chaperone that regulates the proper folding, stability, and function of multiple mutated and wild type signaling proteins that promote malignant phenotypes. Numerous clinical trials are investigating the activity of the Hsp90 inhibitor IPI-504. Since Hsp90 is a novel cancer target that is ubiquitously expressed in normal cells, a comprehensive evaluation of potential cardiac effects, including the risk of ventricular arrhythmia, was performed in two Phase I trials. Methods: ECG data were pooled and analyzed from 60 pts in two-open label Phase I trials of patients with advanced cancers. Pts received 90 to 400 mg/m2 of IPI-504 IV twice weekly for 2 out of 3 weeks. Subset analyses for 35 pts who received the MTD of 400 mg/m2 were performed. ECGs were obtained in triplicate at 5, 60, and 360 minutes after IPI-504 infusion. Interpretation was conducted at a central, independent laboratory. Results: Over 6,500 ECGs were obtained from 60 pts. At the MTD 3,000 ECGs were obtained from 35 patients. No ventricular arrhythmias or changes in QTcF of ≥60 msec were noted, and no statistically significant relationship between the concentration or dose of IPI-504 and QTcF was observed. At the MTD 5 minutes post infusion, changes from baseline were observed in QTcF (5.4 ms increase), heart rate (15.2 bpm decrease), and PR interval (27.9 ms increase). All of these changes reversed by 6 hours post-infusion and no clinical hemodynamic disturbances were observed. Conclusions: In phase I studies, IPI-504 was not associated with any significant ventricular arrhythmia and no clinically significant QTcF interval changes were noted. These studies did show however that IPI-504 administration was associated with transient, dose-related bradycardia and PR interval lengthening, suggestive of autonomic effects associated with the drug infusion. No clinically significant and IPI-504 related cardiac safety events were observed at the MTD dose of 400 mg/m2. Given these findings, appropriate monitoring of heart rate immediately post-infusion is recommended during further studies with IPI-504.

[Table: see text]

Dilated cardiomyopathy and sensorineural hearing loss: a heritable syndrome that maps to 6q23-24

BACKGROUND

Dilated cardiomyopathy (DCM) and sensorineural hearing loss (SNHL) are prevalent disorders that occur alone or as components of complex multisystem syndromes. Multiple genetic loci have been identified that, when mutated, cause DCM or SNHL. However, the isolated coinheritance of these phenotypes has not been previously recognized.

METHODS AND RESULTS

Clinical evaluations of 2 kindreds demonstrated autosomal-dominant transmission and age-related penetrance of both SNHL and DCM in the absence of other disorders. Moderate-to-severe hearing loss was evident by late adolescence, whereas ventricular dysfunction produced progressive congestive heart failure after the fourth decade. DNA samples from the larger kindred (29 individuals) were used to perform a genome-wide linkage study. Polymorphic loci on chromosome 6q23 to 24 were coinherited with the disease (maximum logarithm of odds score, 4.88 at locus D6S2411). The disease locus must lie within a 2.8 cM interval between loci D6S975 and D6S292, a location that overlaps an SNHL disease locus (DFNA10). However, DFNA10 does not cause cardiomyopathy. The epicardin gene, which encodes a transcription factor expressed in the myocardium and cochlea, was assessed as a candidate gene by nucleotide sequence analysis; no mutations were identified.

CONCLUSIONS

A syndrome of juvenile-onset SNHL and adult-onset DCM is caused by a mutation at 6q23 to 24 (locus designated CMD1J). Recognition of this cardioauditory disorder allows for the identification of young adults at risk for serious heart disease, thereby enabling early intervention. Definition of the molecular cause of this syndrome may provide new information about important cell physiology common to both the ear and heart.

Missense mutations in the rod domain of the lamin A/C gene as causes of dilated cardiomyopathy and conduction-system disease

BACKGROUND

Inherited mutations cause approximately 35 percent of cases of dilated cardiomyopathy; however, few genes associated with this disease have been identified. Previously, we located a gene defect that was responsible for autosomal dominant dilated cardiomyopathy and conduction-system disease on chromosome 1p1-q21, where nuclear-envelope proteins lamin A and lamin C are encoded by the LMNA (lamin A/C) gene. Mutations in the head or tail domain of this gene cause Emery-Dreifuss muscular dystrophy, a childhood-onset disease characterized by joint contractures and in some cases by abnormalities of cardiac conduction during adulthood.

METHODS

We evaluated 11 families with autosomal dominant dilated cardiomyopathy and conduction-system disease. Sequences of the lamin A/C exons were determined in probands from each family, and variants were confirmed by restriction-enzyme digestion. The genotypes of the family members were ascertained.

RESULTS

Five novel missense mutations were identified: four in the alpha-helical-rod domain of the lamin A/C gene, and one in the lamin C tail domain. Each mutation caused heritable, progressive conduction-system disease (sinus bradycardia, atrioventricular conduction block, or atrial arrhythmias) and dilated cardiomyopathy. Heart failure and sudden death occurred frequently within these families. No family members with mutations had either joint contractures or skeletal myopathy. Serum creatine kinase levels were normal in family members with mutations of the lamin rod but mildly elevated in some family members with a defect in the tail domain of lamin C.

CONCLUSIONS

Genetic defects in distinct domains of the nuclear-envelope proteins lamin A and lamin C selectively cause dilated cardiomyopathy with conduction-system disease or autosomal dominant Emery-Dreifuss muscular dystrophy. Missense mutations in the rod domain of the lamin A/C gene provide a genetic cause for dilated cardiomyopathy and indicate that this intermediate filament protein has an important role in cardiac conduction and contractility.

Familial dilated cardiomyopathy locus maps to chromosome 2q31

BACKGROUND

Inherited gene defects are an important cause of dilated cardiomyopathy. Although the chromosome locations of some defects and 1 disease gene (actin) have been identified, the genetic etiologies of most cases of familial dilated cardiomyopathy remain unknown.

METHODS AND RESULTS

We clinically evaluated 3 generations of a kindred with autosomal dominant transmission of dilated cardiomyopathy. Nine surviving and affected individuals had early-onset disease (ventricular chamber dilation during the teenage years and congestive heart failure during the third decade of life). The disease was nonpenetrant in 2 obligate carriers. To identify the causal gene defect, linkage studies were performed. A new dilated cardiomyopathy locus was identified on chromosome 2 between loci GCG and D2S72 (maximum logarithm of odds [LOD] score=4.86 at theta=0). Because the massive gene encoding titin, a cytoskeletal muscle protein, resides in this disease interval, sequences encoding 900 amino acid residues of the cardiac-specific (N2-B) domain were analyzed. Five sequence variants were identified, but none segregated with disease in this family.

CONCLUSIONS

A dilated cardiomyopathy locus (designated CMD1G) is located on chromosome 2q31 and causes early-onset congestive heart failure. Although titin remains an intriguing candidate gene for this disorder, a disease-causing mutation is not present in its cardiac-specific N2-B domain.

A gene for non-syndromic autosomal dominant progressive postlingual sensorineural hearing loss maps to chromosome 14q12-13

We report a novel locus responsible for postlingual progressive sensorineural hearing loss (designated DFNA9) that maps to chromosome 14q12-13. A large kindred with autosomal dominant transmission of non-syndromic hearing loss was clinically studied. Hearing in affected individuals deteriorated at approximately 20 years of age and progressed to anacusis in the fifth decade. A random genome-wide search using polymorphic short tandem repeats demonstrated linkage with D14S121 (maximum two point LOD score = 6.19, theta = 0). Haplotype analysis of recombination events defined a 9 cM disease interval, between D14S252 and D14S49.

Mutations in the cardiac myosin binding protein-C gene on chromosome 11 cause familial hypertrophic cardiomyopathy

Familial hypertrophic cardiomyopathy (FHC) is an autosomal dominant disorder manifesting as cardiac hypertrophy with myocyte disarray and an increased risk of sudden death. Mutations in five different loci cause FHC and 3 disease genes have been identified: beta cardiac myosin heavy chain, alpha tropomyosin and cardiac troponin T. Because these genes encode contractile proteins, other FHC loci are predicted also to encode sarcomere components. Two further FHC loci have been mapped to chromosomes 11p13-q13 (CMH4, ref. 6) and 7q3 (ref. 7). The gene encoding the cardiac isoform of myosin binding protein-C (cardiac MyBP-C) has recently been assigned to chromosome 11p11.2 and proposed as a candidate FHC gene. Cardiac MyBP-C is arrayed transversely in sarcomere A-bands and binds myosin heavy chain in thick filaments and titin in elastic filaments. Phosphorylation of MyBP-C appears to modulate contraction. We report that cardiac MyBP-C is genetically linked to CMH4 and demonstrate a splice donor mutation in one family with FHC and a duplication mutation in a second. Both mutations are predicted to disrupt the high affinity, C-terminal, myosin-binding domain of cardiac MyBP-C. These findings define cardiac MyBP-C mutations as the cause of FHC on chromosome 11p and reaffirm that FHC is a disease of the sarcomere.

Assignment of the human a-tropomyosin gene TPM3 to 1q22-->q23 by fluorescence in situ hybridisation

The human tropomyosin 3 (TPM3) gene was previously localized to chromosome 1. The non-muscle isoform of the TPM3 gene product becomes fused to a gene product from the tyrosine kinase receptor gene (NTRK1), previously localized to 1q23-->q24, to generate an active oncogene. Two sequence tagged sites spanning three exons and two introns in the carboxy coding region of the gene were used to localize TPM3 to 1q22-->q23 by fluorescence in situ hybridization. This localization now places the NTRK1 and TPM3 genes in close proximity, so that a gene fusion rearrangement would not be cytologically detected. The 1q22-->q23 localization of TPM3 is within the NEM1 locus associated with autosomal dominant nemaline myopathy, making TPM3 a candidate for this disorder.

A gene defect that causes conduction system disease and dilated cardiomyopathy maps to chromosome 1p1-1q1

Longitudinal evaluation of a seven generation kindred with an inherited conduction system defect and dilated cardiomyopathy demonstrated autosomal dominant transmission of a progressive disorder that both perturbs atrioventricular conduction and depresses cardiac contractility. To elucidate the molecular genetic basis for this disorder, a genome-wide linkage analysis was performed. Polymorphic loci near the centromere of chromosome 1 demonstrated linkage to the disease locus (maximum multipoint lod score = 13.2 in the interval between D1S305 and D1S176). Based on the disease phenotype and map location we speculate that gap junction protein connexin 40 is a candidate for mutations that result in conduction system disease and dilated cardiomyopathy.

Alpha-tropomyosin and cardiac troponin T mutations cause familial hypertrophic cardiomyopathy: a disease of the sarcomere

We demonstrate that missense mutations (Asp175Asn; Glu180Gly) in the alpha-tropomyosin gene cause familial hypertrophic cardiomyopathy (FHC) linked to chromosome 15q2. These findings implicated components of the troponin complex as candidate genes at other FHC loci, particularly cardiac troponin T, which was mapped in this study to chromosome 1q. Missense mutations (Ile79Asn; Arg92Gln) and a mutation in the splice donor sequence of intron 15 of the cardiac troponin T gene are also shown to cause FHC. Because alpha-tropomyosin and cardiac troponin T as well as beta myosin heavy chain mutations cause the same phenotype, we conclude that FHC is a disease of the sarcomere. Further, because the splice site mutation is predicted to function as a null allele, we suggest that abnormal stoichiometry of sarcomeric proteins can cause cardiac hypertrophy.

A familial hypertrophic cardiomyopathy locus maps to chromosome 15q2

We report that a gene responsible for familial hypertrophic cardiomyopathy (FHC) in a kindred with a mild degree of cardiac hypertrophy maps to chromosome 15q2. The gene encoding cardiac actin, located on chromosome 15q, was analyzed and excluded as a candidate for FHC at this locus. Two additional families with typical FHC were studied and the disorder in one also maps to the chromosome 15q2 locus. The maximum combined multipoint logarithm of odds score in the two linked families is 6.02. Although these two kindreds reside in the same country, we believe that their disorder is caused by independent mutations in the 15q2 locus because of the clinical and genotypic differences between affected individuals. Mutations in at least four loci can cause FHC: chromosomes 14q1 (beta cardiac myosin heavy chain gene), 1q3, and 15q2 and another unidentified locus, suggesting substantial genetic heterogeneity.

A disease locus for familial hypertrophic cardiomyopathy maps to chromosome 1q3

Familial hypertrophic cardiomyopathy (FHC) is caused by missense mutations in the beta cardiac myosin heavy chain (MHC) gene in less than half of affected individuals. To identify the location of another gene involved in this disorder, a large family with FHC not linked to the beta MHC gene was studied. Linkage was detected between the disease in this family and a locus on chromosome 1q3 (maximum multipoint lod score = 8.47). Analyses in other families with FHC not linked to the beta MHC gene, revealed linkage to the chromosome 1 locus in two and excluded linkage in six. Thus mutations in at least three genetic loci can cause FHC. Three sarcomeric contractile proteins--troponin I, tropomyosin and actin--are strong candidate FHC genes at the chromosome 1 locus.

Progress in familial hypertrophic cardiomyopathy: molecular genetic analyses in the original family studied by Teare

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Delay to invasive investigation and revascularisation for coronary heart disease in south west Thames region: a two tier system?

OBJECTIVES

To assess the accessibility of invasive investigation and revascularisation procedures in the management of coronary heart disease in a defined population in the South West Thames region over 10 years, and to audit the performance of both the NHS and the private sector.

DESIGN

Analysis of all patient referrals to the regional cardiothoracic centres for coronary heart disease during 1979-88.

SETTING

North West Surrey District Health Authority, which had a mean catchment population of 205,000 during the study period. The health district is one of the 13 in the South West Thames region.

PATIENTS

823 patients aged 34-80 years with suspected coronary heart disease, 204 of whom were referred for private investigation and 619 were referred within the NHS. The NHS referrals were mainly to St Thomas's Hospital during 1979-83 and to St George's Hospital during 1984-8.

MAIN OUTCOME MEASURES

Difference in time to investigation and intervention between the NHS and the private patients.

RESULTS

After some variation in earlier years the mean (SD, range) waiting times from referral to cardiac catheterisation and then revascularisation increased progressively in NHS patients, to 115.8 (126.5, 22-482) days and 305.9 (164.4, 22-620) days respectively in 1988. There was no significant change over the 10 years in waiting times within the private sector, with a mean of 17.2 (18.2, 1-62) days to angiography and 22.8 (14.5, 2-152) days to surgery. Fifteen people on the NHS waiting list died of probable cardiac causes. No people on the private waiting list died.

CONCLUSIONS

The performance of the NHS system in South West Thames region in response to emergency referral is adequate. The waiting time to routine investigation and revascularisation is prolonged and seems to be worsening despite increased investigative and surgical activity by the regional centre. The delays may subject NHS patients to unnecessary risk, which is not shared by private patients.