Can Hospital Discharge Databases Be Used to Follow Ischemic Stroke Incidence?

The obstetrical consequences of ischemic stroke in women of childbearing age

PURPOSE

Although recurrence risk is a major concern for women having had an ischemic stroke (IS) and who are planning a pregnancy, studies on recurrence risk and pregnancy outcomes are scarce and heterogeneous.

METHODS

This retrospective study assessed women aged 15-44 years with a diagnosis of ischemic stroke admitted in the Lyon Stroke Centre, France, between January 2009 and December 2013. The primary outcome was stroke recurrence during pregnancy or the post-partum period. Secondary outcomes were pregnancy complications.

RESULTS

Overall, 104 women with a prior ischemic stroke were included. Mean age at the time of the stroke was 36 ± 6.7 years old. Stroke etiology was large-artery atherosclerosis for 1 woman, cardioembolism for 23 women, and undetermined for 55 women. No antiphospholipid syndrome was found. Among them, 29 women had 58 subsequent pregnancies. Overall, there were three IS recurrence (2.9%), but none occurred during pregnancy. There were 27 miscarriages (47% of pregnancies), two pre-eclampsia (3%), and one stillbirth (1.7%).

CONCLUSIONS

We observed no recurrence of IS during pregnancy. The study also highlighted that the risk of miscarriages was higher than general population and that of stillbirth should be further studied.

Stroke health management: Novel strategies for the prevention of recurrent ischemic stroke

Objectives

The aim of the study was to assess the effect of the stroke health management model on the prognosis and recurrence of mild to moderate ischemic stroke, guided by the stroke health manager based on the patients' needs. In addition, up-to-date evidence of healthcare resource allocation, planning, and optimization is provided.

Methods

The current research was a retrospective, observational, single-center, history-controlled study with patients divided into two groups, namely, the intervention group and the control group, following the guidance of the stroke health manager. The control group patients received standard medical care during hospitalization, which consisted of advice on healthy lifestyle choices carried out by the bed nurse, but no structured education, WeChat group, or clinical consultation was included. The intervention group patients, in addition to the standard medical care, received health management and health education from the stroke health manager, and after hospital discharge, the patients were followed up over the telephone by the health manager to see if there was any recurrence or readmission.

Results

From 1 January 2018 to 31 December 2020, 382 patients with acute ischemic stroke were enrolled in this study. Through the univariate regression analysis, we found that SHM intervention was associated with a significantly lower risk of recurrence (HR = 0.459). We constructed a nomogram based on the significant variables from the regression analysis and also analyzed the association between the control group and the SHM intervention group among all subgroups using the Cox proportional hazards model to assess the effect of the stroke health management model. Most patients in this study had a total risk point between 170 and 270. The C-index value was 0.76, and the time-dependent AUC for predicting recurrence was >0.7.

Conclusion

The stroke health manager-guided management model based on patients' needs can better control the risk factors of stroke and significantly reduce the recurrence rate of mild to moderate ischemic stroke within 1 year.

Trends in hospitalisation for ischaemic stroke in young adults in the region of Murcia (Spain) between 2006 and 2014

INTRODUCTION

Recent studies conducted in Europe and the United States suggest upward trends in both incidence and hospitalisation rates for ischaemic stroke in young adults; however, data for Spain are scarce. This study analyses the trend in hospitalisation due to ischaemic stroke in adults aged under 50 years in the region of Murcia between 2006 and 2014.

METHOD

We performed a retrospective study of patients discharged after hospitalisation due to cerebrovascular disease (CVD); data were obtained from the regional registry of the Minimum Basic Data Set. Standardised rates were calculated, disaggregated by age and CVD subtype. Time trends were analysed using joinpoint regression to obtain the annual calculated standardised rate and the annual percentage of change (APC).

RESULTS

A total of 27 064 patients with CVD were discharged during the 9-year study period. Ischaemic stroke was the most frequent subtype (61.0%). In patients aged 18 to 49 years, the annual number of admissions due to ischaemic stroke increased by 26%, and rates by 29.2%; however, the joinpoint regression analysis showed no significant changes in the trend (APC=2.74%, P≥.05). By contrast, a downward trend was identified in individuals older than 49 (APC=-1.24%, P<.05).

CONCLUSIONS

No significant changes were observed in the rate of hospitalisation due to ischaemic stroke among young adults, despite the decline observed in older adults. Identifying the causes of these disparate trends may be beneficial to the development of specific measures targeting younger adults.

Factors Associated with Stroke Coding Quality: A Comparison of Registry and Administrative Data

BACKGROUND

The International Statistical Classification of Diseases and Related Health Problems, 10th Revision, Australian Modification (ICD-10-AM) codes are commonly used to identify patients with diseases or clinical conditions for epidemiological research. We aimed to determine the diagnostic agreement and factors associated with a clinician-assigned stroke diagnosis in a national registry and the ICD-10-AM codes recorded in government-held administrative data.

MATERIALS AND METHODS

Data from 39 hospitals (2009-2013) participating in the Australian Stroke Clinical Registry (AuSCR) were linked and merged with person-level administrative data. The AuSCR clinician-assigned stroke diagnosis was the reference standard. Concordance was defined as agreement between the clinician-assigned diagnosis and the ICD-10-AM codes for acute stroke or transient ischemic attack (TIA) (ICD-10-AM codes: I61-I64, G45.9). Multivariable logistic regression was undertaken to assess factors associated with coded diagnostic concordance.

RESULTS

A total of 14,716 patient admissions were included (46% female, 63% ischemic, 14% intracerebral hemorrhage [ICH], 18% TIA and 5% unspecified stroke based on the reference standard). Principal ICD-10-AM code concordance was ICH: 76.7%; ischemic stroke: 72.2%; TIA: 80.2%; unspecified stroke: 50.8%. Factors associated with a greater odds of ischemic stroke concordance included: treatment in a stroke unit (adjusted Odds Ratio, aOR:1.58; 95% confidence interval (CI) 1.37, 1.82); length of stay >4 days (aOR:1.30; 95% CI 1.17, 1.45); and discharge destination other than home (Residential care aOR:1.57; 95% CI 1.24, 1.96; Inpatient rehabilitation aOR:1.63; 95% CI 1.43, 1.86).

CONCLUSIONS

Diagnostic concordance varied based on stroke type. Future research to improve the quality of coding for stroke should focus on patients not treated in stroke units or with shorter lengths of stay where documentation in medical records may be limited.

Validity of Acute Cardiovascular Outcome Diagnoses Recorded in European Electronic Health Records: A Systematic Review

BACKGROUND

Electronic health records are widely used in cardiovascular disease research. We appraised the validity of stroke, acute coronary syndrome and heart failure diagnoses in studies conducted using European electronic health records.

METHODS

Using a prespecified strategy, we systematically searched seven databases from dates of inception to April 2019. Two reviewers independently completed study selection, followed by partial parallel data extraction and risk of bias assessment. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value estimates were narratively synthesized and heterogeneity between sensitivity and PPV estimates were assessed using I2.

RESULTS

We identified 81 studies, of which 20 validated heart failure diagnoses, 31 validated acute coronary syndrome diagnoses with 29 specifically recording estimates for myocardial infarction, and 41 validated stroke diagnoses. Few studies reported specificity or negative predictive value estimates. Sensitivity was ≤66% in all but one heart failure study, ≥80% for 91% of myocardial infarction studies, and ≥70% for 73% of stroke studies. PPV was ≥80% in 74% of heart failure, 88% of myocardial infarction, and 70% of stroke studies. PPV by stroke subtype was variable, at ≥80% for 80% of ischaemic stroke but only 44% of haemorrhagic stroke. There was considerable heterogeneity (I2 >75%) between sensitivity and PPV estimates for all diagnoses.

CONCLUSION

Overall, European electronic health record stroke, acute coronary syndrome and heart failure diagnoses are accurate for use in research, although validity estimates for heart failure and individual stroke subtypes were lower. Where possible, researchers should validate data before use or carefully interpret the results of previous validation studies for their own study purposes.

Accuracy of identifying incident stroke cases from linked health care data in UK Biobank

OBJECTIVE

In UK Biobank (UKB), a large population-based prospective study, cases of many diseases are ascertained through linkage to routinely collected, coded national health datasets. We assessed the accuracy of these for identifying incident strokes.

METHODS

In a regional UKB subpopulation (n = 17,249), we identified all participants with ≥1 code signifying a first stroke after recruitment (incident stroke-coded cases) in linked hospital admission, primary care, or death record data. Stroke physicians reviewed their full electronic patient records (EPRs) and generated reference standard diagnoses. We evaluated the number and proportion of cases that were true-positives (i.e., positive predictive value [PPV]) for all codes combined and by code source and type.

RESULTS

Of 232 incident stroke-coded cases, 97% had EPR information available. Data sources were 30% hospital admission only, 39% primary care only, 28% hospital and primary care, and 3% death records only. While 42% of cases were coded as unspecified stroke type, review of EPRs enabled a pathologic type to be assigned in >99%. PPVs (95% confidence intervals) were 79% (73%-84%) for any stroke (89% for hospital admission codes, 80% for primary care codes) and 83% (74%-90%) for ischemic stroke. PPVs for small numbers of death record and hemorrhagic stroke codes were low but imprecise.

CONCLUSIONS

Stroke and ischemic stroke cases in UKB can be ascertained through linked health datasets with sufficient accuracy for many research studies. Further work is needed to understand the accuracy of death record and hemorrhagic stroke codes and to develop scalable approaches for better identifying stroke types.

Spatial distribution and differences of stroke occurrence in the Rhone department of France (STROKE 69 cohort)

In France, 110,000 patients are admitted to hospital per year for stroke. Even though the relationship between stroke and risk factors such as low socio-economic status is well known, research in the spatial distribution (SD) of stroke as a contributing risk factor is less documented. Understanding the geographic differences of the disease may improve stroke prevention. In this study, a statistical spatial analysis was performed using a French cohort (STROKE 69) to describe spatial inequalities in the occurrence of stroke. STROKE 69 was a cohort study of 3,442 patients, conducted in the Rhône department of France, from November 2015 to December 2016. The cohort included all consecutive patients aged 18 years or older, with a likelihood of acute stroke within 24 hours of symptoms onset. Patients were geolocated, and incidence standardized rates ratio were estimated. SD models were identified using global spatial autocorrelation analysis and cluster detection methods. 2,179 patients were selected for analysis with spatial autocorrelation methods, including 1,467 patients with stroke, and 712 with a transient ischemic attack (TIA). Within both cluster detection methods, spatial inequalities were clearly visible, particularly in the northern region of the department and western part of the metropolitan area where rates were higher. Geographic methods for SD analysis were suitable tools to explain the spatial occurrence of stroke and identified potential spatial inequalities. This study was a first step towards understanding SD of stroke. Further research to explain SD using socio-economic data, care provision, risk factors and climate data is needed in the future.

Temporal trends in the accuracy of hospital diagnostic coding for identifying acute stroke: A population-based study

Introduction

Administrative hospital diagnostic coding data are increasingly being used in identifying incident and prevalent stroke cases, for outcome audit and for 'big data' research. Validity of administrative coding has varied in previous studies, but little is known about the temporal trends of coding accuracy, which could bias analyses.

Patients and methods

Using all incident and recurrent strokes in a population-based cohort (Oxford Vascular Study/OXVASC) with multiple sources of ascertainment as the reference, we determined the temporal trends in sensitivity and positive predictive value of hospital diagnostic codes for identifying acute stroke from 2002 to 2017.

Results

Of 1883 hospitalised strokes, 1341 (71.2%) were correctly identified by coding. Sensitivity of coding improved over time for all strokes (p_trend = 0.005) and for incident cases (p_trend = 0.002). Of 1995 apparent stroke admissions identified by International Classification of Disease-10 stroke codes (I60-I68), 1588 (79.6%) used the stroke-specific codes (I60-I61/I63-I64). Positive predictive value was higher with the use of specific codes (83.2% vs. 69.2% for all codes) and highest if combined with the first admission only (88.5%), particularly during more recent time periods (2014-2017 = 90.3%). Of 2254 OXVASC incident strokes, 833 (37.0%) were not hospitalised. Sensitivity of coding increased over time for non-disabling stroke (p_trend = 0.001), but not for disabling/fatal stroke (p_trend = 0.40).

Conclusions

Although accuracy of hospital diagnostic coding for identifying acute strokes improved over the last 15 years, residual insensitivity supports linkage to other sources in large epidemiological studies. Moreover, differences in the time trends of coding sensitivity in relation to stroke severity might bias studies of trends in stroke outcome if only administrative coding is used.

Detection of complicated ectopic pregnancies in the hospital discharge database: A validation study

Objective

Complicated ectopic pregnancies with severe bleeding (CEPSB) are life-threatening situations and should be considered maternal near-miss cases. Previous studies have found an association between severe maternal morbidity secondary to CEPSB and substandard care. Almost all women with CEPSB are hospitalized, generating administrative and medical records. The objective of this study was to propose a method to measure the validity of the hospital discharge database (HDD) to detect CEPSB among hospital stays in two gynecological units.

Methods

We included all hospital stays of women who were 18–45 years old and hospitalized for acute pelvic pain or/and metrorrhagia in the two hospitals. The HDD was compared to medical data (gold standard). Two algorithms constructed from the International Classification of Disease (ICD-10) and Common Classification of Medical Procedures (CCAM), were applied to the HDD: a “predefined algorithm” according to coding guidelines and a “pragmatic algorithm” based on coding practices. Sensitivity, specificity and positive likelihood-ratios were calculated. False negatives and positives were analyzed to describe coding practices.

Results

Among 370 hospital stays included, 52 were classified as CEPSB cases. The “predefined algorithm” gave a sensitivity of 23.1% (95% CI: 11.6–34.5) and a specificity of 99.1% (95% CI: 98.0–100.0) to identify CEPSB. The “pragmatic algorithm” gave a sensitivity of 63.5% (95% CI: 50.4–76.5) and a specificity of 94.7% (95% CI: 92.2–97.5) to identify CEPSB. Coding errors (77.6%) were due to misuse of diagnosis codes and because complications were not coded.

Conclusion

HDD is not reliable enough to detect CEPSB due to incorrect coding practices. However, it could be an ideal tool to monitor quality of care if a culture in data quality assessment is developed to improve quality of medical information.

Hospital burden of coronary artery disease: Trends of myocardial infarction and/or percutaneous coronary interventions in France 2009-2014

BACKGROUND

Currently, cardiovascular disease (CVD) is widely acknowledged to be the first leading cause of fatality in the world with 31% of all deaths worldwide and is predicted to remain as such in 2030. Furthermore, CVD is also a major cause of morbidity in adults worldwide. Among these diseases, the coronary artery disease (CAD) is the most common cause, accounting for over 40% of CVD deaths. Despite a decline in mortality rates, the consequences of more effective preventive and management programs, the burden of CAD remains significant. Indeed, the rise in the prevalence of modifiable risk factors due to changes in lifestyle and health behaviors has further increased the burden of this epidemic. Our objective was to evaluate the hospital burden of CAD via MI trends and Percutaneous Coronary Intervention (PCI) in the French Prospective Payment System (PPS).

METHODS

MI/PCI were identified in the national PPS database from 2009 to 2014 for patients aged 20 to 99, living in metropolitan France. We examined hospitalisation, readmission and mortality trends using standardised rates.

RESULTS

Over the six-year period, we identified 678,021 patients, representing 900,121 stays of which, 215,224 had a MI and a PCI. Admission trends increased by nearly 25%. Acute MI cases increased every year, with an alarming increase in women, and more specifically in young women. Men were 3 times more hospitalised than women, who were older. A North-South divide was noted. Twenty seven percent of patients experienced readmission within 1 month. Trajectories of care were significantly different by sex and age. Overall in-hospital death was 3.3%, decreasing by 15% during the period. The highest adjusted mortality rates were observed for inpatients aged <40 or >80.

CONCLUSION

We outlined the public health burden of this condition and the importance of improving the trajectories of care as an aid for better care.

What is the evolution of stroke unit's accessibility in metropolitan France from 2009 to 2014? A trend analysis of over 600 000 patients using national hospital databases

OBJECTIVES

We aimed to study trends in stroke unit (SU) admission during a period of their deployment in France and to assess whether this led to better and more equitable access to this specialised care.

DESIGN

Analysis of records from the national hospital database.

SETTING

All acute care hospitals in metropolitan France for the period 2009-2014.

PARTICIPANTS

Over 600 000 patients admitted in acute care with a main diagnosis of stroke.

MAIN OUTCOME MEASURES

Admission to a SU.

RESULTS

Between 2009 and 2014, the number of stroke admissions rose from 93 728 to 109 456, and the proportion of SU admission from 23% to 44%. Overall, characteristics associated with higher probability of SU admission were: male gender, younger age, ischaemic stroke type, medium level of comorbidity and larger size of town of residence. Although likelihood of SU admission increased in all patients' categories during the study period, we identified steeper positive temporal trends among older patients, those with more comorbidities and those residing in medium or small towns (all p values <0.001), suggesting a 'catching up' phenomena. Temporal trends of men and women did not differ however.

CONCLUSIONS

Admission to SU nearly doubled in France between 2009 and 2014. Faster trends observed for patients with lower admission to SU suggest that equity in access has improved over the period.

Secondary Prevention Three and Six Years after Stroke Using the French National Insurance Healthcare System Database

BACKGROUND

Secondary prevention is inadequate in the first 2 years after stroke but what happens after that is less documented. The aim of this study was to assess the use and the adherence to preventive drugs 3 and 6 years after experiencing a transient ischemic attack (TIA) or an ischemic stroke (IS).

METHODS

The population study was from the AVC69 cohort (IS or TIA admitted in an emergency or stroke unit in the Rhône area, France, for an IS or a TIA during a 7-month period). Medication use was defined as ≥1 purchase during the studied year and adherence as Continuous Measure of Medication Acquisition ≥0.8 using the French medical insurance health care funding database.

RESULTS

The study population consisted of 210 patients at 3 years and 163 patients at 6 years. Medication use at 3 and 6 years was, respectively, 80.9 and 79.8% for antithrombotics, 69.1 and 66.3% for antihypertensives, 60.5 and 55.2% for statins and 48.6 and 46.6% for optimal treatment defined as the treatment achieved by the use of the 3 drugs. Adherence to each class was good at 3 years and tends to decrease at 6 years.

CONCLUSIONS

More than one patient out of 2 do not use the optimal preventive treatment.

Administrative data underestimate acute ischemic stroke events and thrombolysis treatments: Data from a multicenter validation survey in Italy

Background

Informing health systems and monitoring hospital performances using administrative data sets, mainly hospital discharge data coded according to International-Classification-Diseases-9edition-Clinical-Modifiers (ICD9-CM), is now commonplace in several countries, but the reliability of diagnostic coding of acute ischemic stroke in the routine practice is uncertain. This study aimed at estimating accuracy of ICD9-CM codes for the identification of acute ischemic stroke and the use of thrombolysis treatment comparing hospital discharge data with medical record review in all the six hospitals of the Florence Area, Italy, through 2015.

Methods

We reviewed the medical records of all the 3915 potential acute stroke events during 2015 across the six hospitals of the Florence Area, Italy. We then estimated sensitivity and Positive Predictive Value of ICD9-CM code-groups 433*1, 434*1 and thrombolysis code 99.10 against medical record review with clinical adjudication. For each false-positive case we obtained the actual diagnosis. For each false-negative case we obtained the primary and secondary ICD9-CM diagnoses.

Results

The medical record review identified 1273 acute ischemic stroke events. The hospital discharge records identified 898 among those (true-positive cases),but missed 375 events (false-negative cases), and identified 104 events that were not eventually confirmed as acute ischemic events (false-positive cases). Code-group specific Positive Predictive Value was 85.7% (95%CI,74.6–93.3) for 433*1 and 89.9% (95%CI, 87.8–91.7) for 434*1 codes. Thrombolysis treatment, as identified by ICD9-CM code 99.10, was only documented in 6.0% of acute ischemic stroke events, but was 13.6% in medical record review.

Conclusions

Hospital discharge data were found to be fairly specific but insensitive in the reporting of acute ischemic stroke and thrombolysis, providing misleading indications about both quantity and quality of acute ischemic stroke hospital care. Efforts to improve coding accuracy should precede the use of hospital discharge data to measure hospital performances in acute ischemic stroke care.

Biases in detection of apparent "weekend effect" on outcome with administrative coding data: population based study of stroke

OBJECTIVES

 To determine the accuracy of coding of admissions for stroke on weekdays versus weekends and any impact on apparent outcome.

DESIGN

 Prospective population based stroke incidence study and a scoping review of previous studies of weekend effects in stroke.

SETTING

 Primary and secondary care of all individuals registered with nine general practices in Oxfordshire, United Kingdom (OXVASC, the Oxford Vascular Study).

PARTICIPANTS

 All patients with clinically confirmed acute stroke in OXVASC identified with multiple overlapping methods of ascertainment in 2002-14 versus all acute stroke admissions identified by hospital diagnostic and mortality coding alone during the same period.

MAIN OUTCOMES MEASURES

 Accuracy of administrative coding data for all patients with confirmed stroke admitted to hospital in OXVASC. Difference between rates of "false positive" or "false negative" coding for weekday and weekend admissions. Impact of inaccurate coding on apparent case fatality at 30 days in weekday versus weekend admissions. Weekend effects on outcomes in patients with confirmed stroke admitted to hospital in OXVASC and impacts of other potential biases compared with those in the scoping review.

RESULTS

 Among 92 728 study population, 2373 episodes of acute stroke were ascertained in OXVASC, of which 826 (34.8%) mainly minor events were managed without hospital admission, 60 (2.5%) occurred out of the area or abroad, and 195 (8.2%) occurred in hospital during an admission for a different reason. Of 1292 local hospital admissions for acute stroke, 973 (75.3%) were correctly identified by administrative coding. There was no bias in distribution of weekend versus weekday admission of the 319 strokes missed by coding. Of 1693 admissions for stroke identified by coding, 1055 (62.3%) were confirmed to be acute strokes after case adjudication. Among the 638 false positive coded cases, patients were more likely to be admitted on weekdays than at weekends (536 (41.0%) v 102 (26.5%); P<0.001), partly because of weekday elective admissions after previous stroke being miscoded as new stroke episodes (267 (49.8%) v 26 (25.5%); P<0.001). The 30 day case fatality after these elective admissions was lower than after confirmed acute stroke admissions (11 (3.8%) v 233 (22.1%); P<0.001). Consequently, relative 30 day case fatality for weekend versus weekday admissions differed (P<0.001) between correctly coded acute stroke admissions and false positive coding cases. Results were consistent when only the 1327 emergency cases identified by "admission method" from coding were included, with more false positive cases with low case fatality (35 (14.7%)) being included for weekday versus weekend admissions (190 (19.5%) v 48 (13.7%), P<0.02). Among all acute stroke admissions in OXVASC, there was no imbalance in baseline stroke severity for weekends versus weekdays and no difference in case fatality at 30 days (adjusted odds ratio 0.85, 95% confidence interval 0.63 to 1.15; P=0.30) or any adverse "weekend effect" on modified Rankin score at 30 days (0.78, 0.61 to 0.99; P=0.04) or one year (0.76, 0.59 to 0.98; P=0.03) among incident strokes.

CONCLUSION

 Retrospective studies of UK administrative hospital coding data to determine "weekend effects" on outcome in acute medical conditions, such as stroke, can be undermined by inaccurate coding, which can introduce biases that cannot be reliably dealt with by adjustment for case mix.

Agreement between routine electronic hospital discharge and Scottish Stroke Care Audit (SSCA) data in identifying stroke in the Scottish population

Background

In Scotland all non-obstetric, non-psychiatric acute inpatient and day case stays are recorded by an administrative hospital discharge database, the Scottish Morbidity Record (SMR01). The Scottish Stroke Care Audit (SSCA) collects data from all hospitals managing acute stroke in Scotland to support and improve quality of stroke care. The aim was to assess whether there were discrepancies between these data sources for admissions from 2010 to 2011.

Methods

Records were matched when admission dates from the two data sources were within two days of each other and if an International Classification of Diseases (ICD) code of I61, I63, I64, or G45 was in the primary or secondary diagnosis field on SMR01. We also carried out a linkage analysis followed by a case-note review within one hospital in Scotland.

Results

There were a total of 22 416 entries on SSCA and 22 200 entries on SMR01. The concordance between SSCA and SMR01 was 16 823. SSCA contained 5593 strokes that were not present in SMR01, whereas SMR01 contained 185 strokes that were not present in SSCA. In the case-note review the concordance was 531, with SSCA containing 157 strokes that were not present in SMR01 and SMR01 containing 32 strokes that were not present in SSCA.

Conclusions

When identifying strokes, hospital administrative discharge databases should be used with caution. Our results demonstrate that SSCA most accurately represents the number of strokes occurring in Scotland. This resource is useful for determining the provision of adequate patient care, stroke services and resources, and as a tool for research.

Accuracy of Electronic Health Record Data for Identifying Stroke Cases in Large-Scale Epidemiological Studies: A Systematic Review from the UK Biobank Stroke Outcomes Group

Objective

Long-term follow-up of population-based prospective studies is often achieved through linkages to coded regional or national health care data. Our knowledge of the accuracy of such data is incomplete. To inform methods for identifying stroke cases in UK Biobank (a prospective study of 503,000 UK adults recruited in middle-age), we systematically evaluated the accuracy of these data for stroke and its main pathological types (ischaemic stroke, intracerebral haemorrhage, subarachnoid haemorrhage), determining the optimum codes for case identification.

Methods

We sought studies published from 1990-November 2013, which compared coded data from death certificates, hospital admissions or primary care with a reference standard for stroke or its pathological types. We extracted information on a range of study characteristics and assessed study quality with the Quality Assessment of Diagnostic Studies tool (QUADAS-2). To assess accuracy, we extracted data on positive predictive values (PPV) and—where available—on sensitivity, specificity, and negative predictive values (NPV).

Results

37 of 39 eligible studies assessed accuracy of International Classification of Diseases (ICD)-coded hospital or death certificate data. They varied widely in their settings, methods, reporting, quality, and in the choice and accuracy of codes. Although PPVs for stroke and its pathological types ranged from 6–97%, appropriately selected, stroke-specific codes (rather than broad cerebrovascular codes) consistently produced PPVs >70%, and in several studies >90%. The few studies with data on sensitivity, specificity and NPV showed higher sensitivity of hospital versus death certificate data for stroke, with specificity and NPV consistently >96%. Few studies assessed either primary care data or combinations of data sources.

Conclusions

Particular stroke-specific codes can yield high PPVs (>90%) for stroke/stroke types. Inclusion of primary care data and combining data sources should improve accuracy in large epidemiological studies, but there is limited published information about these strategies.

Risk of Major Cardiovascular Events in People with Down Syndrome

BACKGROUND

Improved medical care over more than five decades has markedly increased life expectancy, from 12 years to approximately 60 years, in people with Down syndrome (DS). With increased survival into late adulthood, there is now a greater need for the medical care of people with DS to prevent and treat aging-related disorders. In the wider population, acquired cardiovascular diseases such as stroke and coronary heart disease are common with increasing age, but the risks of these diseases in people with DS are unknown. There are no population-level data on the incidence of acquired major cerebrovascular and coronary diseases in DS, and no data examining how cardiovascular comorbidities or risk factors in DS might impact on cardiovascular event incidence. Such data would be also valuable to inform health care planning for people with DS. Our objective was therefore to conduct a population-level matched cohort study to quantify the risk of incident major cardiovascular events in DS.

METHODS AND FINDINGS

A population-level matched cohort study compared the risk of incident cardiovascular events between hospitalized patients with and without DS, adjusting for sex, and vascular risk factors. The sample was derived from hospitalization data within the Australian state of Victoria from 1993-2010. For each DS admission, 4 exact age-matched non-DS admissions were randomly selected from all hospitalizations within a week of the relevant DS admission to form the comparison cohort. There were 4,081 people with DS and 16,324 without DS, with a total of 212,539 person-years of observation. Compared to the group without DS, there was a higher prevalence in the DS group of congenital heart disease, cardiac arrhythmia, dementia, pulmonary hypertension, diabetes and sleep apnea, and a lower prevalence of ever-smoking. DS was associated with a greater risk of incident cerebrovascular events (Risk Ratio, RR 2.70, 95% CI 2.08, 3.53) especially among females (RR 3.31, 95% CI 2.21, 4.94) and patients aged ≤ 50 years old. The association of DS with ischemic strokes was substantially attenuated on adjustment for cardioembolic risk (RR 1.93, 95% CI 1.04, 3.20), but unaffected by adjustment for atherosclerotic risk. DS was associated with a 40-70% reduced risk of any coronary event in males (RR 0.58, 95% CI 0.40, 0.84) but not in females (RR 1.14, 95% CI 0.73, 1.77).

CONCLUSIONS

DS is associated with a high risk of stroke, expressed across all ages. Ischemic stroke risk in DS appears mostly driven by cardioembolic risk. The greater risk of hemorrhagic stroke and lower risk of coronary events (in males) in DS remain unexplained.

Validation of Stroke and Thrombolytic Therapy in Korean National Health Insurance Claim Data

Background and Purpose

The claims data of the Korean National Health Insurance (NHI) system can be useful in stroke research. The aim of this study was to validate the accuracy of hospital discharge data used for NHI claims in identifying acute stroke and use of thrombolytic therapy.

Methods

The hospital discharge data of 1,811 patients with stroke-related diagnosis codes were obtained from Jeju National University Hospital (JNUH) and Seoul Medical Center (SMC). Three algorithms were tested to identify discharges with acute stroke [ischemic stroke (IS), intracranial hemorrhage (ICH), or subarachnoid hemorrhage (SAH)]: 1) all diagnosis codes up to nine positions, 2) one primary diagnosis and one secondary diagnosis, and 3) only one primary diagnosis code. Reviews of medical records were considered the gold standards.

Results

Overall, the degree of agreement (κ) was higher for algorithms 1 and 2 than for algorithm 3, and the sensitivity and specificity of the first two algorithms for IS and SAH were both >90%, with almost perfect agreement (κ=0.83-0.84) in the JNUH data set. Regarding ICH, only algorithm 1 yielded an almost perfect agreement (κ=0.82). In the SMC data set, almost perfect agreement was found for both ICH and SAH in all three algorithms. In contrast, the three algorithms yielded a range of agreement levels, though all substantial, for IS. Almost perfect agreement was obtained for use of thrombolytic therapy in both data sets (κ=0.91-0.99).

Conclusions

Discharge with hemorrhagic stroke and use of thrombolytic therapy were identified with high reliability in administrative discharge data. A substantial level of agreement was also obtained for IS, despite variation between the algorithms and data sets.

Validity of Diagnostic Codes for Acute Stroke in Administrative Databases: A Systematic Review

OBJECTIVE

To conduct a systematic review of studies reporting on the validity of International Classification of Diseases (ICD) codes for identifying stroke in administrative data.

METHODS

MEDLINE and EMBASE were searched (inception to February 2015) for studies: (a) Using administrative data to identify stroke; or (b) Evaluating the validity of stroke codes in administrative data; and (c) Reporting validation statistics (sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), or Kappa scores) for stroke, or data sufficient for their calculation. Additional articles were located by hand search (up to February 2015) of original papers. Studies solely evaluating codes for transient ischaemic attack were excluded. Data were extracted by two independent reviewers; article quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies tool.

RESULTS

Seventy-seven studies published from 1976-2015 were included. The sensitivity of ICD-9 430-438/ICD-10 I60-I69 for any cerebrovascular disease was ≥ 82% in most [≥ 50%] studies, and specificity and NPV were both ≥ 95%. The PPV of these codes for any cerebrovascular disease was ≥ 81% in most studies, while the PPV specifically for acute stroke was ≤ 68%. In at least 50% of studies, PPVs were ≥ 93% for subarachnoid haemorrhage (ICD-9 430/ICD-10 I60), 89% for intracerebral haemorrhage (ICD-9 431/ICD-10 I61), and 82% for ischaemic stroke (ICD-9 434/ICD-10 I63 or ICD-9 434&436). For in-hospital deaths, sensitivity was 55%. For cerebrovascular disease or acute stroke as a cause-of-death on death certificates, sensitivity was ≤ 71% in most studies while PPV was ≥ 87%.

CONCLUSIONS

While most cases of prevalent cerebrovascular disease can be detected using 430-438/I60-I69 collectively, acute stroke must be defined using more specific codes. Most in-hospital deaths and death certificates with stroke as a cause-of-death correspond to true stroke deaths. Linking vital statistics and hospitalization data may improve the ascertainment of fatal stroke.

Validation of Stroke Diagnosis in the National Registry of Hospitalized Patients in the Czech Republic

BACKGROUND

Stroke is a common cause of mortality and morbidity in Eastern Europe. However, detailed epidemiological data are not available. The National Registry of Hospitalized Patients (NRHOSP) is a nationwide registry of prospectively collected data regarding each hospitalization in the Czech Republic since 1998. As a first step in the evaluation of stroke epidemiology in the Czech Republic, we validated stroke cases in NRHOSP.

METHODS

Any hospital in the Czech Republic with a sufficient number of cases was included. We randomly selected 10 of all 72 hospitals and then 50 patients from each hospital in 2011 stratified according to stroke diagnosis (International Classification of Diseases Tenth Revision [ICD-10] cerebrovascular codes I60, I61, I63, I64, and G45). Discharge summaries from hospitalization were reviewed independently by 2 reviewers and compared with NRHOSP for accuracy of discharge diagnosis. Any disagreements were adjudicated by a third reviewer.

RESULTS

Of 500 requested discharge summaries, 484 (97%) were available. Validators confirmed diagnosis in NRHOSP as follows: transient ischemic attack (TIA) or any stroke type in 82% (95% confidence interval [CI], 79-86), any stroke type in 85% (95% CI, 81-88), I63/cerebral infarction in 82% (95% CI, 74-89), I60/subarachnoid hemorrhage in 91% (95% CI, 85-97), I61/intracerebral hemorrhage in 91% (95% CI, 85-96), and G45/TIA in 49% (95% CI, 39-58). The most important reason for disagreement was use of I64/stroke, not specified for patients with I63.

CONCLUSIONS

The accuracy of coding of the stroke ICD-10 codes for subarachnoid hemorrhage (I60) and intracerebral hemorrhage (I61) included in a Czech Republic national registry was high. The accuracy of coding for I63/cerebral infarction was somewhat lower than for ICH and SAH.

Declining rates of fatal and nonfatal intracerebral hemorrhage: epidemiological trends in Australia

Background

A recent systematic review of epidemiological studies reported intracerebral hemorrhage (ICH) incidence and mortality as unchanged over time; however, comparisons between studies conducted in different health services obscure assessment of trends. We explored trends in ICH rates in a large, representative population in New South Wales, Australia's most populous state (≈7.3 million).

Methods and Results

Adult hospitalizations with a principal ICH diagnosis from 2001 to 2009 were linked to death registrations through to June 30, 2010. Trends for overall, fatal, and nonfatal ICH rates within 30 days and fatal rates for 30‐day survivors at 365 days were calculated. There were 11 332 ICH patient admissions meeting eligibility criteria, yielding a crude hospitalization rate of 25.2 per 100 000 (age‐standardized rate: 17.2). Age‐ and sex‐adjusted overall rates significantly declined by an average of 1.6% per year (P=0.03). Fatal ICH declined by an average of 2.6% per year (P=0.004). For 30‐day survivors, a nonsignificant decline of 2.3% per year in fatal ICH at 365 days was estimated (P=0.17). Male sex and birth in the Oceania region and Asia were associated with an increased ICH risk, although this depended on age. Approximately 12% of ICH admissions would be prevented if the socioeconomic circumstances of the population equated with those of the least disadvantaged.

Conclusions

Overall and fatal ICH rates have fallen in this large Australian population. Improvements in cardiovascular prevention and acute care may explain declining rates. There was no evidence of an increase in devastated survivors because the longer term mortality of 30‐day survivors has not increased over time.

Trends over time in the risk of stroke after an incident transient ischemic attack

BACKGROUND AND PURPOSE

Long-term population trends in the early risk of stroke after transient ischemic attack (TIA) are unknown. We hypothesized that there has been an appreciable decline in the risk of stroke after TIA for the last decade.

METHODS

Population-level cohort study from Victoria, Australia (population 5.6 million), using linked data from hospitals, emergency departments, and death records (2001-2011), with a 2-year clearance period to define incident TIAs. Age-specific rates/1000, yearly incident rate ratios, and age-sex-adjusted risk of stroke after TIA were computed.

RESULTS

The mean age of 46 971 patients with TIA was 71 (SD=15), 52% women. In patients ≥65 years, annual TIA rates declined between 2001 and 2011 from 5.8 to 4.8/1000 (men) and from 5.3 to 4.2/1000 (women). Yearly incident rate ratios were 0.97 (95% confidence interval, 0.96-0.98) in men and 0.97 (95% confidence interval, 0.97-0.98) in women. Overall, the 90-day stroke risk was 3.1%. Age-sex-adjusted risk of stroke at 90 days after a TIA decreased by 3% per year (odds ratio for the effect of year, 0.97; 95% confidence interval, 0.95-0.99). Male sex, direct discharge from emergency departments, public hospital care, stroke unit care, and absence of vascular risk factors were associated with a downward yearly trend of stroke within 90 days of TIA.

CONCLUSIONS

Over the last 10 years, there has been a measurable decline in the 90-day risk of stroke after an incident TIA and overall decline in rates of TIA in Victoria, Australia. These trends may reflect improved primary and secondary prevention efforts for the last decade.

Trends of hospitalized acute stroke care in Germany from clinical trials to bedside. Comparison of nation-wide administrative data 2008-2012

Promising advances in stroke medicine have been reported recently regarding specialized stroke unit (SU) care, expansion of the time window of iv thrombolysis (IVT), mechanical thrombectomy (MT), and decompressive hemicraniectomy (DHC) for malignant brain infarction. It remains unclear to what extent new evidence of therapeutic procedures is transferred to the "real-world" of everyday hospital care. We analyzed epidemiologic and procedural therapeutic trends of hospitalized acute stroke patients in Germany by the comparison of administrative hospital data of the years 2008 (n=219,359) and 2012 (n=239,394). Proportion of specialized SU care rose from 43.4% to 56.9%. Even in age-matched analysis women were less likely to obtain this procedure. Rate of IVT increased from 5.6% to 10.2%. 32% of IVT therapies in 2012 were performed in patients over 80 years. Number of MT increased exponentially from 298 to 3906 procedures. Number of DHC did not increase significantly (2008=636; 2011=796). A strong momentum in transferring scientific insights to the "real-world" stroke care in Germany was documented. Increase of IVT therapy is largely due to the increase of off-label treatment. Almost every 46 th patient <80 years was treated by MT in 2012. Despite proven benefits in selected patients, utilization of DHC remained almost stable.