The over-riding objectives of this SENTI-MELC study are:

1) To map out the places of care and death, and the care setting trajectory of patients at the end of life

2) To describe the caregivers involved in end-of-life care, and the actual treatments and care provided at the end of life; and more specifically to study the role of the general practitioner and of specialized multidisciplinary palliative care services

3) To study the patient, residence, and healthcare characteristics associated with places of care, caregivers, and end-of-life care provided.

The objective of this report is to present the protocol of the study used for the data collection in 2005 and 2006. We hope that our experience in Belgium will be useful to others, in particular to countries with analogue surveillance networks of general practitioners 3233 who wish to initiate end-of-life care research into their registrations. The described methodology will also serve as detailed reference for the method section of future SENTI-MELC publications as results from the study emerge.

General practice is highly accessible in Belgium: almost all of the population (95%), including care home residents, have a regular general practitioner (GP) who they consult regularly 36. Hence, GPs can provide a good public health perspective on end-of-life care and dying in the country and it would be possible to generate a population-based sample of deaths via GPs. Therefore, we decided to work with a representative sample of GPs in Belgium.

A Sentinel Network of General Practitioners is a network of practices or community based physicians who monitor one, several or an exhaustive list of health problems on a regular or continuing basis. The information from these practices is used to monitor the health of the entire population 3237. The Belgian Sentinel Network of GPs is a nationwide network, operational since 1979, and has proved to be a reliable surveillance system for a wide variety of health-related epidemiological data e.g. on diabetes, stroke, cancer, accidents 33383940414243.

The GPs in the Network collect data via continuous and weekly paper-and-pencil registrations using a standardized registration form. Each registration programme lasts minimally one year. Each year, about 8 different themes are surveyed. The general objectives of a Sentinel Network of GPs are: to evaluate public health problems and their importance within the general population; to continuously observe certain health problems over time for example to study the impact of prevention campaigns; and to study the management and follow-up of health problems by the general practitioners. Recorded data must concern an important health problem not subject to surveillance of another system, unless the Sentinel Network provides complementary information to this end. The participation of the GPs is voluntary. Feedback is regularly distributed to the participants, concerned authorities, the medical press, scientific associations and interested individuals. The turnover of the GPs, from year to year, is low, which contributes to the collection of data of high scientific quality. Also, only regularly participating GPs (i.e. who register at least 26 weeks per year) are included for data analyses. The Sentinel Network is funded by the regional governments of Belgium and co-ordinated by the Scientific Institute of Public Health 44.

In 2005, the first year of this study, the Network consisted of 181 regularly participating GP practices (205 GPs), who were representative of all 10,578 GPs in Belgium in terms of age, gender and geographical distribution, and also of the GPs in the Northern (Dutch-speaking) and Southern (French-speaking) regions of Belgium separately. The Network covered 1.75% of the total Belgian population 4044.

The unit of measurement in this study was the death case. Primary inclusion criteria were:

- every patient, part of the practice of the GP, who had died (certified deaths and deaths of which they were informed afterwards)

- aged one year or older

In order to focus this study on care delivered at the end of life or on dying patients (i.e. patients who were theoretically able to receive care in the terminal phase of life) we additionally excluded all deaths that had occurred "suddenly and totally unexpectedly 2845."

For the purpose of this study, the GPs registered deaths on a weekly standardized registration form, during 2 consecutive years (2005–2006) from January 1^st until December 31^st. To shorten the time between death and registration – hence preventing recall bias as much as possible – the physicians were instructed to register all deaths, immediately after being informed about the patient's death. GPs use patient records and information coming from hospital physicians as much as possible when filling in the forms. To control for possible non-response (e.g. GPs who forgot to report one of their deaths), all GPs received a summary of all reported deaths after each year of registration. GPs were asked to verify all these reported deaths and indicate if there were deaths that were not yet reported. If this was the case, we asked about basic demographic information (age, sex, place and cause of death) of the unreported deaths.

In this study, the terminal phase under consideration was defined as the last three months of life of patients that died non-suddenly 34464748.

Transitions between end-of-life care settings were defined as moves or changes in location of care, during the last three months of life. Home (or with relatives, in service flats), care home (elderly/nursing home), hospital and (inpatient) palliative care unit, were differentiated. Care setting trajectories are a combination of moves between different settings.

Caregivers involved in patient care were subdivided into informal caregivers (e.g. partner, child, sibling, friends) and formal caregivers (specialized multidisciplinary palliative care services, GP, clinical specialist, nurse, caretaker/home carer, spiritual caregiver, physio-, occupational-, speech therapist).

End-of-life care was measured in terms of end-of-life care goals i.e. main treatment aim (cure, prolonging life, or palliative/comfort/supportive care), specific potentially life-prolonging and palliative treatments received, and physical, psychosocial and/or spiritual content of care 12. Other end-of-life practices measured were the absence/presence of continuous deep sedation until death of the patient, and of medical end-of-life decisions with possible life-shortening effect i.e. (1) non-treatment decisions; (2) alleviation of pain or other symptoms, in dosages which are large enough to include the hastening of death as a possible or certain side-effect; and (3) physician-assisted dying (including euthanasia, physician-assisted suicide, and life-ending without the patient's explicit request). This categorisation was based on a pre-existing internationally validated framework 272849.

To develop the registration form for this study, we selected instruments used in other (Dutch) retrospective and quantitative studies whenever possible 1727285051525354. In case a specific concept could not be measured with an existing instrument, questions were developed on the basis of relevant literature and in dialogue with the Belgian Scientific Institute of Public Health (coordinating the Sentinel Network of GPs) and with a counselling project Advisory Board consisting of 5 MDs (of which 4 GPs), a palliative care physician, 2 psychologists, a medical sociologist, a health scientist, an anthropologist and a representative from a home care nursing organisation. We also copied questions from the official death certificates in Belgium, in order to optimize comparison afterwards.

Because Belgium consists of two large regions in which Dutch or French is spoken, the instrument was first developed in Dutch and then translated into French via forward-backward procedure.

The standardized weekly registration form is shown in Additional File 1 in English (forward translation from the Dutch version). The first part A concerned several patient- and residence characteristics and was filled in for all patients who met the primary inclusion criteria. Questions from Part A based on official death certificates were Q2, Q3, Q4, Q5, Q8, Q10, Q11 and Q12. Question 17 was taken from previously designed questionnaires in Belgium and the Netherlands 272845. Questions designed in dialogue with the Scientific Institute of Public Health and the counselling Advisory Board were Q6, Q7, Q9, Q13, Q14, Q15 and Q16.

For all patients who had died non-suddenly, the GPs registered part B consisting of: places of care and wishes for place of death, the caregivers involved during the last three months of life, the (goals of) end-of-life care and medical decision-making. Several aspects of the medical care provided were measured using three separate time frames: last week, second to fourth week and second to third month before death. Questions from Part B based on previously designed questionnaires in Belgium and the Netherlands 1727285051525354 were Q3, Q4, Q5 (partly), Q6 and Q9 until Q16. Literature concerning life-sustaining therapies and indicators of aggressive and palliative care 112155565758 additionally guided the development of Q5. Questions designed in the counselling Advisory Board were Q1, Q2, Q7 and Q8.

The quantitative registration instrument implied that all items had closed-ended response options. Also, in order to avoid the confounding effect that positive or negative connotations of several terms may or may not have (for example euthanasia or terminal sedation), we only used wording that describes the actual medical practices.

Finally, GPs were sent accompanying instructions at the beginning of each year, clearly stating the inclusion criteria of the study, and clarifying the manner in which the questions concerning cause of death and care setting trajectory needed to be filled in.

The Scientific Institute of Public Health, co-ordinating the Belgian Sentinel Network of GPs, asks the GPs to give written informed consent at the beginning of each year, after being fully informed about the objectives and method of the research themes. The registration of deaths is part of this procedure.

Furthermore, strict procedures regarding patient anonymity are employed 59. Every patient that is registered within the network receives an anonymous reference from the GP him/herself. An independent "Trust Service Provider" is responsible for supplementary anonymisation of patient information i.e. the patient's date of birth is registered by the GP but replaced with the patient's age before data-entry, and postal code of habitual residence is transformed into more aggregate indicators such as province and region of care. Concerning the GPs' identity, all his/her identification codes are replaced in the data files with anonymous codes during data cleaning.

The protocol of the present study was approved by the Ethical Review Board of Brussels University Hospital of the Vrije Universiteit Brussel (2004).

The feasibility of the study design and the measurement instruments have been tested in an extensive pilot study of 3 months in 2004 60. The pilot study was also intended to estimate the number of non-sudden deaths that GPs would register per year, and the statistical power for the analyses of the main study in 2005 and 2006. The physicians were instructed to register all deaths of patients, aged one year or older, on a continuous basis during the months of inclusion (13 consecutive weeks), as well as the last death before this period.

In 2004, 176 GP practices reported one or more deaths. In total 502 deaths were reported, of which 466 were part of the GPs' practices. Patients who were not part of the GPs' practices (whose death was certified by the GP) were excluded. Sixty-eight percent (n = 318) of this group died during the inclusion period, and 62% (n = 214) of the latter group had died non-suddenly.

On the basis of this pilot study, the registration instrument was slightly adapted. It was estimated that 1310 patients who were part of the GPs' practices would be registered in 2005 by the 181 participating practices, and that 890 of these patients would have died non-suddenly.

Several control measures are used to ensure data quality and to limit missing data. Data are entered weekly using a dbase-based programme. Range and skip checks prevent key-punching errors. Automatic follow-up of missing data for key variables and a consistency check during data-entry with the possibility of contacting GPs by phone, improve data quality. Key-punch errors are corrected via double data-entry.

Data cleaning and data analyses for this study are performed using SPSS14.0 (SPPS Inc). During data cleaning, no manual changes are made. Instead, all operations are stored via SPPS syntax-files to create a working data file. Databases are stored with a central data manager at the Scientific Institute of Public Health. To answer the first two descriptive objectives of the study concerning the places of care, and medical care provided, we plan to use mainly descriptive statistics i.e. valid percentages and 95% Confidence Intervals. To study the characteristics associated with these outcome measures (objective 3), we will use multivariate logistic regression analyses.

To verify if a representative population-based sample of deaths can be obtained via this representative sample of GPs, we will evaluate whether the deaths registered by the Sentinel Network of GPs are comparable in terms of age, sex, place of death and cause of death, to the deaths occurring within the general population (using bivariate and multivariate statistics). Since there are no recent mortality statistics available for the Southern Region of Belgium, the comparison will be made only for the data from the Northern and Brussels Capital Region (66% of the total population).

The Belgian Sentinel Network of General Practitioners is representative of all GPs in Belgium, has a long tradition in scientific research (operational since 1979), is very flexible in terms of acceptability of new registrations, and is very stable in terms of participating GPs. The GPs are highly motivated to monitor various health-related problems over long and repeated periods, thus have not been selected on the basis of a specific interest in end-of-life research. Because detailed information concerning the care provided is not always available from the patients' medical files, a registration directly with GPs has an important surplus value. Since general practice is highly accessible in Belgium, a representative sample of the entire population can be monitored. Comparisons between the national vital statistics and the (age- and sex-specific) incidences of stroke mortality and suicide registered via this Sentinel Network, and between several national and international cancer registries and the cancer incidence registered via this Sentinel Network, have shown that the Sentinel Network can provide information representative for the whole population of Belgium 38626364.

A specific strength of this mortality follow-back study itself is that retrospective recall bias found in other retrospective research designs 2835, will be limited, because of the weekly registrations, leaving little time between death and registration. Also, identification of non-sudden deaths as denominator is an advantage over other prospective and retrospective designs that have been criticized for selecting patients solely on the basis of diagnose or cause of death. Not all patients with a cancer diagnose, for example, also die of cancer or receive care with an end-of-life intent 344765. By avoiding to include patients that died suddenly and unexpectedly, we will be able to study care that was truly delivered in the context of a dying process. On the basis of literature, we judged the last three months of life as a relevant study period 34464748.

The surveillance system also has several weaknesses. Because in Belgium, there are no patient lists per practice, the population denominator (the "sentinel population") is not precisely defined and has to be estimated on the basis of annual total number of patient encounters in the participating practices 40. Also, the registration form is to be kept simple, and time-consuming questions should be avoided in a surveillance system. Consequently, in-depth study of some aspects of care is generally not possible via this type of registration research 3243.

Possible weaknesses of the mortality study are the retrospective data collection approach making reconstruction of all care provided in the final three months of life difficult 35 and the reliance on GPs to report care and decisions at the end of life, including care delivered to patients in hospitals or decisions taken by hospital physicians. An underestimation of specific types of care provided or decisions taken is thus possible. The extent of this problem will be studied in detail.

Firstly, while data gathering with the Sentinel Network in 2005–2006 focused on the processes of care delivered, a similar data gathering with the same network has been set up, aimed at investigating outcomes of quality of end-of-life care and at developing quality indicators. Data will be gathered from 2007 until 2009. Secondly, because data can be gathered over time, we will, in the long-run, evaluate the monitoring potential of this instrument. The results could potentially serve as baseline data to monitor end-of-life care over time. Thirdly, a study with Sentinel Networks creates important opportunities for international comparative research. Most European countries have at least one sentinel network of GPs 323337. The death registration that was started up in Belgium in 2005 has also been implemented in the Netherlands, and other European countries (Italy, Switzerland, Spain) are currently investigating if analogue studies are possible.

In conclusion, societal knowledge concerning the end of life has been limited to place and causes of death. Additionally, and for the first time in Belgium, with the SENTI-MELC study, we will build a public health database on how people are dying and what care they are receiving at the end of life. It will be possible to make practice and healthcare policy recommendations on the basis of this information.