Adaptation and validation of the Charlson Index for Read/OXMIS coded databases

Khan, Nada; Perera, Rafael; Harper, Stephen; Rose, Peter W.

doi:10.1186/1471-2296-11-1

Cited by 322 publications

(310 citation statements)

References 23 publications

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“…Although the models with Khan et al's adapted Charlson Index performed well, 30 fewer diseases are represented in this comorbidity index than in the popular Elixhauser Index, which is also partly derived from the original Charlson Index. 45,46 While there is no indication of inappropriate use in the English general practice population, the effects of taxonomical incompatibility should also be considered, as Khan et al's adapted Charlson Index was translated from International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes, 47 which are not used in England.…”

Section: Resultsmentioning

confidence: 97%

Adverse events recorded in English primary care: observational study using the General Practice Research Database

Tsang

Bottle²,

Majeed³

et al. 2013

Br J Gen Pract

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BackgroundMore accurate and recent estimates of adverse events in primary care are necessary to assign resources for improvement of patient safety, while predictors must be identified to ameliorate patient risk. AimTo determine the incidence of recorded iatrogenic harm in general practice and identify risk factors for these adverse events. Design and settingCross-sectional sample of 74 763 patients at 457 English general practices between 1 January 1999 and 31 December 2008, obtained from the General Practice Research Database. MethodPatient age at study entry, sex, ethnicity, deprivation, practice region, duration registered at practice, continuity of care, comorbidities, and health service use were extracted from the data. Adverse events were defined by Read Codes for complications of care (Chapters S, T, and U). Crude and adjusted analyses were performed by Poisson regression, using generalised estimating equations. ResultsThe incidence was 6.0 adverse events per 1000 person-years (95% confidence interval [CI] = 5.74 to 6.27), equivalent to eight adverse events per 10 000 consultations (n = 2 540 877). After adjustment, patients aged 65-84 years (risk ratio [RR] = 5.62, 95% CI = 4.58 to 6.91; P<0.001), with the most consultations (RR = 2.14, 95% CI = 1.60 to 2.86; P<0.001), five or more emergency admissions (RR = 2.08, 95% CI = 1.66 to 2.60; P<0.001), or the most diseases according to expanded diagnosis clusters (RR = 8.46, 95% CI = 5.68 to 12.6; P<0.001) were at greater risk of adverse events. Patients registered at their practice for the longest periods of time were less at risk of an adverse event (RR = 0.40, 95% CI = 0.35 to 0.47; P<0.001). ConclusionThe low incidence of recorded adverse events is comparable with other studies. Temporal sequencing of risk factors and case ascertainment would benefit from data triangulation. Future studies may explore whether first adverse events predict future incidents.

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Section: Resultsmentioning

confidence: 97%

Adverse events recorded in English primary care: observational study using the General Practice Research Database

Tsang

Bottle²,

Majeed³

et al. 2013

Br J Gen Pract

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“…Comorbidity was calculated based upon 17 chronic illnesses and their associated weights, as defined by Khan et al . 46, and was incorporated as a time‐varying score (0, 1, 2 or more).…”

Section: Methodsmentioning

confidence: 99%

The impact of buprenorphine and methadone on mortality: a primary care cohort study in the United Kingdom

et al. 2018

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AimsTo estimate whether opioid substitution treatment (OST) with buprenorphine or methadone is associated with a greater reduction in the risk of all‐cause mortality (ACM) and opioid drug‐related poisoning (DRP) mortality.DesignCohort study with linkage between clinical records from Clinical Practice Research Datalink and mortality register.SettingUK primary care.ParticipantsA total of 11 033 opioid‐dependent patients who received OST from 1998 to 2014, followed‐up for 30 410 person‐years.MeasurementsExposure to methadone (17 373, 61%) OST episodes or buprenorphine (9173, 39%) OST episodes. ACM was available for all patients; information on cause of death and DRP was available for 5935 patients (54%) followed‐up for 16 363 person‐years. Poisson regression modelled mortality by treatment period with an interaction between OST type and treatment period (first 4 weeks on OST, rest of time off OST, first 4 weeks off OST, rest of time out of OST censored at 12 months) to test whether ACM or DRP differed between methadone and buprenorphine. Inverse probability weights were included to adjust for confounding and balance characteristics of patients prescribed methadone or buprenorphine.FindingsACM and DRP rates were 1.93 and 0.53 per 100 person‐years, respectively. DRP was elevated during the first 4 weeks of OST [incidence rate ratio (IRR) = 1.93 95% confidence interval (CI) = 0.97–3.82], the first 4 weeks off OST (IRR = 8.15, 95% CI = 5.45–12.19) and the rest of time out of OST (IRR = 2.13, 95% CI = 1.47–3.09) compared with mortality risk from 4 weeks to end of treatment. Patients on buprenorphine compared with methadone had lower ACM rates in each treatment period. After adjustment, there was evidence of a lower DRP risk for patients on buprenorphine compared with methadone at treatment initiation (IRR = 0.08, 95% CI = 0.01–0.48) and rest of time on treatment (IRR = 0.37, 95% CI = 0.17–0.79). Treatment duration (mean and median) was shorter on buprenorphine than methadone (173 and 40 versus 363 and 111, respectively). Model estimates suggest that there was a low probability that methadone or buprenorphine reduced the number of DRP in the population: 28 and 21%, respectively.ConclusionsIn UK general medical practice, opioid substitution treatment with buprenorphine is associated with a lower risk of all‐cause and drug‐related poisoning mortality than methadone. In the population, buprenorphine is unlikely to give greater overall protection because of the relatively shorter duration of treatment.

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“…Comorbidities prior to diagnosis were derived from GP records and included those within a recent adaptation of the Charlson Comorbidity index [17]. A measure of deprivation was available from CPRD records [18].…”

Section: Covariatesmentioning

confidence: 99%

Metformin use and survival from lung cancer: A population-based cohort study

et al. 2016

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word count: 222 Manuscript word count: 1,472Number of tables and figures: 2 Abbreviations: BMI, body mass index; CIs, confidence intervals; CPRD, Clinical Practice Research Datalink; DDD, daily defined dose; GP, general practitioner; HR, hazard ratio; NCDR, National cancer Data Repository; ONS, Office of National Statistics; UK, United Kingdom; WHO, World Health Organisation. AbstractPreclinical evidence suggests that metformin, a widely prescribed anti-diabetic drug, may inhibit lung cancer progression. We investigated whether metformin use was associated with decreased risk of cancer-specific mortality in lung cancer patients. This study included newly diagnosed lung cancer patients (identified from English National Cancer Data Repository, 1998-2009) with type 2 diabetes (based on UK Clinical Practice Research Datalink prescriptions and diagnosis records). Lung cancer deaths occurring up to 2012 were identified using Office of National Statistics mortality data and the association between metformin use (before and after diagnosis) and risk of lung cancer-specific mortality was calculated using Cox regression models. In analysis of 533 patients, we found a weak non-significant reduction in lung cancer-specific mortality with metformin use after diagnosis (adjusted HR, 0.86; 95% CI, 0.68-1.09). No association was evident for metformin use before diagnosis and cancer-specific mortality in analysis of 1,350 patients (adjusted HR, 0.97; 95% CI, 0.86, 1.11). Associations were similar by duration of use. In addition, after adjustment for potential confounders, there was little evidence of an association between the use of other anti-diabetic medications (either before or after diagnosis) and lung cancer-specific mortality; including sulfonylureas, insulin or other anti-diabetic medications (such as thiazolidinediones). Overall, the results from this population-based study provide little evidence of a protective association between metformin use and cancer mortality in lung cancer patients.

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Adaptation and validation of the Charlson Index for Read/OXMIS coded databases

Cited by 322 publications

References 23 publications

Adverse events recorded in English primary care: observational study using the General Practice Research Database

Adverse events recorded in English primary care: observational study using the General Practice Research Database

The impact of buprenorphine and methadone on mortality: a primary care cohort study in the United Kingdom

Metformin use and survival from lung cancer: A population-based cohort study

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