stroke is of major importance for public health internationally as stroke is the second most common cause of death globally and is a major cause of disability worldwide.1,2 the 30-day case - fatality among patients with stroke has dropped in recent decades but remains overall between 10% and 20% in most western populations . monitoring the quality of stroke care has a high international priority . the world health organization ( who ) cardiovascular disease program aims at developing standards of care as well as feasible surveillance methods to monitor prevention and control initiatives for cardiovascular diseases , including stroke .
furthermore , a number of countries monitor the quality of stroke care at a national level in established stroke registries , for example , sweden , the us , germany , and austria .
denmark first launched national clinical guidelines for the acute treatment and care of patients with stroke in 2003 , and they have since been updated regularly .
these guidelines recommend early initiation of treatment , care , and rehabilitation , and are in line with international consensus guidelines from the american heart association and the european stroke organisation . the danish stroke registry ( dsr )
was established in 2003 as part of the danish national indicator project , which was a national quality improvement initiative aimed at monitoring and improving quality of care using evidence - based quality of care indicators.3 the dsr is now a nationwide clinical registry and part of the danish clinical registries  a national improvement program , which is an umbrella organization encompassing clinical registries in denmark .
the activities of the registry are coordinated by a multidisciplinary steering group , including physicians , nurses , physiotherapists , and occupational therapists .
the members of the steering groups have been appointed by the relevant scientific societies and stakeholders .
all danes ( total population , aged 18 or older by january 2016 : 3,964,146 ) are provided tax - supported health care by the danish health care system allowing free access to hospital care and general practitioners .
patients with acute medical conditions , including stroke , are exclusively admitted to public hospitals .
all hospitals departments regularly treating patients with acute stroke and transient ischemic attack ( tia ) are required by law to report data to the dsr .
data are collected prospectively and reported to the dsr using a web - based interface .
all patients ( 18 years ) admitted to danish hospitals with acute stroke , as defined by who criteria , that is , an acute disturbance of focal or global cerebral function with symptoms lasting more than 24 hours or leading to death of presumed vascular origin , are eligible for inclusion in the dsr . only patients with symptom onset within the last week
this includes patients with intracerebral hemorrhage and ischemic stroke ( international classification of diseases tenth edition : i63 , infarction ; i61 , hemorrhage ; and i64 , unspecified ) .
in addition , patients with tia ( ie , patients with symptoms lasting up to 24 hours ) are included .
patients with subarachnoidal or epidural hemorrhage , subdural hematoma , retinal infarct , and infarct caused by trauma , infection , or an intracranial malignant process are excluded .
patients with diffuse symptoms , such as isolated vertigo or headache , and asymptomatic patients with infarct detected only by computed tomography or magnetic resonance imaging scan are also excluded .
the registry included > 130,000 events by the end of 2014 , including 10,822 strokes and 4,227 tias registered in 2014 .
the sensitivity and predictive value of the registration of patients in the dsr was estimated to be > 90% in 2009.4 although it can not entirely be excluded that the completeness of the registration and regular assessments of the validity of the registration is always to be recommended in clinical registries , there is no indication based on the number of registered patients and the diagnostic work up of the patients that the registration practice has changed substantially over time .
a total of 18 process and four result indicators covering the early phase of stroke have been identified by the steering group ( table 1 ) .
the process indicators reflect key recommendations from the national clinical guidelines and the dsr consequently monitors the implementation of these guidelines at danish hospitals .
patients are classified as eligible or noneligible for the specific processes of care depending on whether the stroke team or physician treating the patient identifies contraindications ; for example , severe dementia in a patient with ischemic stroke and atrial fibrillation precluding oral anticoagulant therapy or rapid spontaneous recovery of motoric symptoms , making early assessment by a physiotherapist and an occupational therapist irrelevant .
a structured audit process is carried out regularly ( every year ) on a national , regional , and local basis to assess critically the quality of the dataset and results .
after the audit process is completed , the data are released publicly with department - level data , including comments on the results from the audit groups and recommendations on how to improve quality of care.5 improvements over the years have been observed for all quality indicators and for some process indicators the improvements have been dramatic , for example , the proportion of relevant patients fulfilling the indicator has doubled or even tripled .
selected key variables in the dsr are presented in table 2 . besides the variables used to assess the quality indicators , the dsr also includes data on a range of prognostic factors .
these factors are used to characterize the included patients and to take differences in case - mix into account when benchmarking departments or when comparing the same department over time .
in addition , supplementary data on intravenous thrombolysis and endovascular therapy are obtained in order to characterize the provided treatments .
formal validation studies on the registered data have not been conducted ; however , the overall quality of the recorded data is most likely high since detailed instructions , including explicit data definitions , are available and data recording practices are examined and discussed by representatives of the hospitals departments reporting to the registry at the yearly audits .
all patients are followed up by individual - level record linkage to other public registries using the civil registry number , which is unique to every danish citizen and enables unambiguous linkages .
information on mortality is obtained from the danish civil registration system , which stores daily updated electronic records of all changes in vital status and migration for the entire danish population , including changes in address , date of emigration , and the exact date of death , since 1968.6 information on unplanned readmissions are obtained from the danish national registry of patients , which is an administrative nationwide public registry that covers all discharges from somatic hospitals in denmark since january 1 , 1977.7 the data include the dates of admission and discharge and up to 20 diagnoses for every discharge classified , since 1994 , according to the danish version of the international classification of diseases tenth edition .
information on functional level 3 months after the day of admission with acute stroke is assessed using the modified rankin score for all patients receiving revascularization therapy ( intravenous thrombolysis or endovascular therapy ) and recorded directly in the dsr .
the dsr has been used in numerous studies covering a broad range of topics , including traditional clinical epidemiological studies on prognosis810 as well as studies on effectiveness of care,1113 disparities of care,14,15 and health economics.16 the registry has been linked extensively with other public registries in many of these studies .
the dsr is an approved clinical quality database by the state serum institute and the danish data protection agency .
it is funded by the danish regions and receives administrative , epidemiological , and biostatistical support from the danish clinical registries .
aggregated data at regional level will be reported annually in a published report , and data will be provided monthly to the regions for use in each region s information system .
the dsr is a national clinical registry which plays an important role as an information source and quality improvement instrument for stroke and tia care in denmark .
 aim of databasethe aim of the danish stroke registry is to monitor and improve the quality of care among all patients with acute stroke and transient ischemic attack ( tia ) treated at danish hospitals.study populationall patients with acute stroke ( from 2003 ) or tia ( from 2013 ) treated at danish hospitals . 
 reporting is mandatory by law for all hospital departments treating these patients . 
 the registry included > 130,000 events by the end of 2014 , including 10,822 strokes and 4,227 tias registered in 2014.main variablesthe registry holds prospectively collected data on key processes of care , mainly covering the early phase after stroke , including data on time of delivery of the processes and the eligibility of the individual patients for each process . 
 the data are used for assessing 18 process indicators reflecting recommendations in the national clinical guidelines for patients with acute stroke and tia . 
 patient outcomes are currently monitored using 30-day mortality , unplanned readmission , and for patients receiving revascularization therapy , also functional level at 3 months poststroke.descriptive datasociodemographic , clinical , and lifestyle factors with potential prognostic impact are registered.conclusionthe danish stroke registry is a well - established clinical registry which plays a key role for monitoring and improving stroke and tia care in denmark . 
 in addition , the registry is increasingly used for research . 
Background and aim of the database
Setting
Study population
Quality indicators
Main variables
Follow-up
Examples of research
Administrative issues and funding
Conclusion