WWW-publications from the WHO MONICA Project
June 1999
Hanna Tolonen1, Marco Ferrario2 and Maddalena Minoja3 for the WHO MONICA Project4
1 MONICA Data Centre, National Public Health Institute, Helsinki, Finland
2 Institute of Biomedical Sciences 'San Gerardo' and Research Centre on
Chronic-Degenerative Diseases, University of Milan, Monza, Italy
3 The School of Public Health, University of Milan, Milan, Italy
4 Annex: Sites and key personnel of the WHO MONICA
Project
Thanks are due to Kari Kuulasmaa for his review and comments on the document and Alun Evans and Annette Dobson who commented on the text.
The MONICA Centres are funded predominantly by regional and national governments, research councils, and research charities. Coordination is the responsibility of the World Health Organization (WHO), assisted by local fund raising for congresses and workshops. WHO also supports the MONICA Data Centre (MDC) in Helsinki. Not covered by this general description is the ongoing generous support of the MDC by the National Public Health Institute of Finland, and a contribution to WHO from the National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA for support of the MDC and the Quality Control Centre for Event Registration in Dundee. The completion of the MONICA Project is generously assisted through a Concerted Action Grant from the European Community. Likewise appreciated are grants from ASTRA Hässle AB, Sweden, Hoechst AG, Germany, Hoffmann-La Roche AG, Switzerland, the Institut de Recherches Internationales Servier (IRIS), France, and Merck & Co. Inc., New Jersey, USA, to support data analysis and preparation of publications.
In the WHO MONICA Project (1), three independent cross-sectional population surveys were carried out in many populations in the 1980s and early 1990s to measure the classical risk factors of the cardiovascular diseases. Questions on awareness and treatment of high cholesterol were introduced in the November 1990 version of the MONICA Manual (2). Since most of the MONICA Collaborating Centres (MCCs) had already started and many had even finished their middle population survey by that time, these new questions were considered optional measurements in this survey. Therefore, the data can be expected to be available for some of the MONICA Collaborating Centres (MCCs) in the middle MONICA survey and for most of them in the final survey. Before the data on awareness of high cholesterol and on dietary and drug treatment of high cholesterol can be effectively used to study the situation in different populations, or to carry out comparisons between populations, certain basic issues of data quality and comparability must be considered.
The MONICA Project has a standard format for data transfer to the MONICA Data Centre (MDC). To facilitate this it is necessary to collect the information in such a format that the data required for the data transfer can be extracted. The MONICA Manual (2) includes four questions related to the awareness and drug treatment of high cholesterol:
| HICH | "Have you ever been told by a doctor or other health worker that you
have high blood cholesterol?" 1 = yes 2 = no (if no, record 8 in items CHDT and CHRX ) 9 = insufficient data |
| CHDT | "Are you on special diet prescribed by a doctor or other health
worker to lower your blood cholesterol level?" 1 = yes 2 = no 3 = uncertain 8 if HICH = 2 9 = insufficient data |
| CHRX | "Are you taking (in the last two weeks) pills or other medicine prescribed by a
doctor to lower your blood cholesterol level?" 1 = yes 2 = no 3 = uncertain 8 if HICH = 2 9 = insufficient data |
| CHRECD | "Have you had your blood cholesterol measured in the last year?" 1 = yes 2 = no 9 = insufficient data |
The survey periods when the data were collected in the MCCs have been reported elsewhere (3)
The main purpose of this quality assessment report is:
The results of this document are reported by Reporting Unit Aggregates (RUAs) which are potential candidates for units of analyses of the MONICA data. The RUAs, their abbreviations and Reporting Units (RUs) are listed in Table 1. The RUAs are identified by the abbreviation and a version letter. For UNK-GLA, which carried out four surveys, this report assesses the third (middle) and fourth (final) survey. In this report, altogether 41 RUAs are considered for the middle MONICA survey and 39 for the final survey.
The questionnaires used in the middle survey in their local language and/or their English translation were available in the MDC for all RUAs (Table 2). The questionnaires used in the final survey were available for all RUAs. In 1991 a questionnaire on the MONICA Population Survey Procedures (Form VI), including a question as to whether the questionnaire was self-administered or completed during an interview, was sent to all MCCs. In 1995 the questionnaire was further checked by the MCCs concerning the final survey.
Data on the items of control of high cholesterol were transferred to the MDC using the MONICA core data transfer format (Form 04, versions 6, 7)(2) .
The age range studied in each RUA is given in Table 1. For the quality assessment all observations within the age group 25-64 were used as the denominator of proportions presented in Tables 5,6, 8 and 10. For Tables 7 and 9 the denominator includes only subjects aware of high cholesterol. No age or sex adjustment was applied to the data.
As reported in Table 2, for the middle and final survey, all RUAs have provided their original questionnaire and/or its English translation. In the final survey two RUAs (ICE-ICE and YUG-NOS) used the MONICA data transfer format (Form04) as their original questionnaire. YUG-NOS translated the questionnaire into Serbo-Croatian but ICE-ICE used the English version as their original questionnaire.
In the middle and final survey one RUA (USA-STA) used both interviewer and self-administered questionnaires. Most RUAs used interviews in the middle (31 RUAs) and final (29 RUAs) surveys (Table 2.).
Findings
In the middle survey the question on HICH was not asked in 28 (68%) RUAs (Table 3). Among the 13 RUAs which asked the question, only three (SPA-CAT, SWE-GOT and SWE-NSW) used the exact MONICA format (Table A.).
From the 10 RUAs whose questions on HICH differed from the MONICA format, 4 (AUS-NEW, FIN-KUO, FIN-NKA and FIN-TUL) did not include the expression "told by a doctor or other health worker". In 5 RUAs (AUS-PER, GER-AUU, GER-AUR, GER-BRE and UNK-GLA) the question was "Have you ever been told that you have any of the following?" and high cholesterol was one of the alternatives listed. In one RUA (FRA-TOU) the question was "Do you have too much cholesterol?".
In the final survey only 2 (5%) RUAs (GER-ERF and NEZ-AUC) did not ask the question on HICH (Table 3.). The exact MONICA format was used in 29 (74%) RUAs (Table A.).
Among the 8 (21%) RUAs whose question on HICH differed from the standard MONICA format, 3 RUAs (FIN-KUO, FIN-NKA and FIN-TUL) omitted the part "told by a doctor or other health worker". 5 (AUS-PER, GER-AUR, GER-AUU, GER-BRE and UNK-GLA) RUAs continued using the question "Have you ever been told that you have any of the following?" where high cholesterol was one of the alternatives given.
|
Standard transfer format, exact MONICA data can be extracted | Different from the standard transfer format, but the exact MONICA data can be extracted | The exact MONICA data cannot be extracted | Question not asked | Total |
|---|---|---|---|---|---|
Mid |
3 (7%) |
10 (24%) |
0 (0%) |
28 (68%) |
41 |
| Fin | 29 (74%) |
8 (21%) |
0 (0%) |
2 (5%) |
39 |
Discussion
In both the middle and final surveys all RUAs which asked the question on HICH but did not use the standard MONICA format, omitting the specification "by doctor or other health worker". This can produce biases in both directions, because the answer could be based on subjective feelings.
Findings
In the middle survey in 33 (80%) RUAs the question on CHDT was not asked. Only two (5%) RUAs (SPA-CAT and SWE-GOT) included a question on CHDT identical to the standard MONICA question (Table 3).
For the 6 (15%) RUAs whose question differed from the standard MONICA form, 5 RUAs have questions which can be transformed into the MONICA format (Table B.). SWE-NSW asked "Have a doctor or other health worker prescribed you a special diet to lower your cholesterol level?", without mentioning if the subject was complying with it. In AUS-NEW the question was "If you are on treatment for high cholesterol, what sort of methods are you using?" and "change in diet" was one of the alternatives listed. In FRA-TOU the question was "Are you presently following a diet?" followed by the question "Which one?". In UNK-GLA the question was "Are you on special diet?" and one of the alternatives was "cholesterol-lowering diet". One RUA (AUS-PER) asked "Which of the following best describes your usual way of eating?" and one of the possible answers was "Fat modified diet to lower blood fat".
Rest of the RUAs have questions which cannot be transformed into MONICA format. In one RUA (GER-BRE) was asked "Do you have or have you ever had one of these diseases?" and elevated cholesterol was one of the alternatives. Included to that question there was the sub-question "Because of it, I was treated in the last 4 weeks:" and the alternative "yes, other measured (for example, diet, medical gymnastics)" was considered as dietary treatment.
In the final survey the question was not asked in four (10%) RUAs (GER-AUR, GER-AUU, GER-ERF and NEZ-AUC). The standard MONICA format was used by 23 (59%) RUAs .
Among 12 (31%) RUAs which had question different from the standard MONICA question in 11 RUAs the MONICA data can be extracted from the local question(s). BEL-CHA and BEL-GHE asked "Have you ever been prescribed a special diet to lower your blood cholesterol?", without specification if it was prescribed by a doctor or other health worker. Two RUAs (AUS-NEW and USA-STA) asked "..., what sort of method(s) are you using?" and diet was one of the alternatives. In LTU-KAU the question was "Are you taking drugs or diet for lowering cholesterol?". UNK-GLA continued using the same question adopted in the middle survey. One RUA (AUS-PER) used the standard MONICA question with the qualification that the subject was on diet "in the last month". In DEN-GLO the question was "Are you on a diet prescribed by a doctor?" and one of the alternative answers was "yes, cholesterol lowering?". In three RUAs (FIN-KUO, FIN-NKA and FIN-TUL) the question was "If your blood cholesterol is measured, did you get instructions about diet to lower blood cholesterol?".
In one RUA (GER-BRE) where the question on CHDT cannot be transformed into the standard MONICA format, the question was "When did a physician or his staff for the last time advise you to eat fat-arm (low-cholesterol) meals?" and identical to as in the middle survey.
|
Standard transfer format, exact MONICA data can be extracted | Different from the standard transfer format, but the exact MONICA data can be extracted | The exact MONICA data cannot be extracted | Question not asked | Total |
|---|---|---|---|---|---|
Mid |
2 (5%) |
5 (12%) |
1 (2%) |
33 (80%) |
41 |
| Fin | 23 (59%) |
11 (28%) |
1 (3%) |
4 (10%) |
39 |
Discussion
Four RUAs in the middle survey (AUS-NEW, AUS-PER, FRA-TOU and UNK-GLA) and two RUAs in the final (LTU-KAU and UNK-GLA) did not specify if the diet was prescribed by a doctor or other health worker. This type of question can cause some deviation from the standard question on CHDT, because it cannot be considered as a specific diet to lower cholesterol. In SWE-NSW in the middle survey and in three RUAs in the final survey (BEL-CHA, BEL-GHE, and GER-BRE) the standard MONICA question was not asked, because it is not clear if the person was really consuming the prescribed diet. Thus, the questions cannot be considered as the standard MONICA item.
One RUA (AUS-PER) in the final survey used the standard MONICA format with the specification "in the last month"; this formulation is expected to produce only minor bias in the results, because the proportion of people who had stopped the diet during the last month, should be reasonably small.
Findings
In the middle survey the question on CHRX was not asked in 26 (63%) RUAs. Only SPA-CAT used the standard MONICA format (Table 3).
For 14 RUAs whose question(s) differed from standard MONICA question, the MONICA data can be extracted (Table C.) for 13. The most common deviation from the standard MONICA item is the omission of the expression "prescribed by a doctor" and/or use of a different time period.
AUS-NEW omitted the expression "prescribed by a doctor" in their question "If you are on treatment for high cholesterol what sort of method are you using?" with alternative "medication".
Among the RUAs whose question was otherwise similar to the standard MONICA question (FRA-TOU, ITA-BRI and UNK-GLA) the phrase "prescribed by a doctor" was omitted and the question referred to the present time. In SWE-GOT question was also similar to the standard MONICA question and only the part "prescribed by a doctor" was omitted.
Another deviation from the standard MONICA format was that the person was asked to list the medicines used. This was the case in 9 RUAs and only in one RUA (SWE-GOT) it was mentioned that medicines should be prescribed by a doctor. Also in this type of question the time period in most of the RUAs was different from two weeks. In BEL-CHA, BEL-GHE, GER-AUR, GER-AUU and UNK-BEL the question referred to the present time. DEN-GLO referred to the past 12 months, and SWE-GOT used the expression "in the last weeks". GER-BRE referred to the past 4 weeks and the question on medicines was part of the question on awareness of high cholesterol.
In one RUA the local question cannot be transformed into the standard MONICA form. In AUS-PER the question on CHRX was "Are you having treatment to lower your blood fat?" without clear specifications if the treatment was with medicines and if they were taken for lowering cholesterol.
In the final survey all 39 RUAs had some kind of question on CHRX. In 17 (44%) RUAs the question was identical to the MONICA format and in remaining 22 RUAs the MONICA data can be extracted form the local questions (Table C.).
Again in the final survey the most common deviation from the standard MONICA format was the omission of the expression "prescribed by a doctor" and/or the use of different time period than 'the last two weeks'. Among 14 RUAs which otherwise had a similar question as the standard MONICA format, 5 RUAs omitted only the part "prescribed by a doctor", 6 RUAs had mentioned "prescribed by a doctor" but used a different time period. In AUS-PER the time period was the last month, and rest used the present time. The remaining 3 RUAs with similar question to the standard MONICA question omitted "prescribed by a doctor" and referred to the present time.
In all 8 RUAs whose question departed further from the standard MONICA format, the time period was different from two weeks. Three RUAs referred to the present time and only one of these used the expression "prescribed by a doctor". In AUS-NEW the question was "If you are on treatment for high cholesterol, what sort of method(s) are you using" and medication was one of the alternatives. LTU-KAU asked "Are you taking drugs or diet for lowering cholesterol?" and USA-STA asked "Did the doctor advise you to take a prescribed medicine?". A longer time period than two weeks was considered in 3 RUAs. DEN-GLO asked "Have you within the last few weeks been taking cholesterol lowering drugs?", GER-BRE kept the same question as in the middle survey which referred to the past 4 weeks. In NEZ-AUC the past 3 months were considered: "What tablets or other medications have you been taking regularly during the last 3 months?".
| Standard transfer format, exact MONICA data can be extracted | Different from the standard transfer format, but the exact MONICA data can be extracted | The exact MONICA data cannot be extracted | Question not asked | Total | |
|---|---|---|---|---|---|
| Mid | 1 (2%) |
13 (32%) |
1 (2%) |
26 (63%) |
41 |
| Fin | 17 (44%) |
22 (56%) |
0 (0%) |
0 (0%) |
39 |
Discussion
Several RUAs did not use the specification "prescribed by a doctor or other health worker", but probably this does not induce a significant bias, because the proportion of people who take medicine without prescription is very low.
The main deviations from the recommended definition of drug treatment for high cholesterol concern the time when subject had last taken the cholesterol lowering drug. The standard data transfer format states "in the last two weeks", but assessment of concurrent treatments at the time of the interview or in the preceding weeks or a few months may be considered equivalent, because it seems unlikely that people under recent treatment had stopped it in the two weeks before the screening. Therefore the bias, if any, is expected to be negligible.
Findings
In the middle survey the question on CHRECD was not asked in 31 (76%) RUAs. Four (10%) RUAs (SPA-CAT, SWE-GOT, SWE-NSW and UNK-GLA) included a question on CHRECD identical to the standard MONICA question (Table 3). Six RUAs asked "When was your cholesterol last measured" and 12 months or 1 year was one of the possible answers (Table D.).
In the final survey the question on CHRECD was not asked in 4 (10%) RUAs (GER-AUR, GER-AUU, GER-ERF and NEZ-AUC). The question on CHRECD was identical to the standard MONICA question in 28 (72%) RUAs. Seven RUAs asked "When was your cholesterol last measured" and 12 months or 1 year was one of the possible answers.
| Standard transfer format, exact MONICA data can be extracted | Different from the standard transfer format, but the exact MONICA data can be extracted | The exact MONICA data cannot be extracted | Question not asked | Total | |
|---|---|---|---|---|---|
| Mid | 4 (10%) |
6 (15%) |
0 (0%) |
31 (76%) |
41 |
| Fin | 28 (72%) |
7 (18%) |
0 (0%) |
4 (10%) |
39 |
Discussion
Six RUAs in the middle survey and 7 RUAs in the final survey asked "When was your cholesterol last measured" and 12 months or 1 year was one of the possible answers. This formulation is very similar to the standard MONICA question.
The MDC checks all population survey core data received from the MCCs at the time they are included in the MONICA database. All possible inconsistencies in the data are reported to the MCC to enable the correction of errors. The following constraints concern items HICH, CHDT, CHRX and CHRECD:
All violations of these constraints were reported to the MCCs for their correction or
confirmation. Data values outside the limits were acceptable, but the MCC had to check
that the values were not due to data errors. The MCCs were only asked to correct values if
they knew that they were incorrect. The currently unresolved constraint violations
concerning data on awareness and treatment of high cholesterol are listed in Appendix 1.
Table 4 presents the availability of data on HICH in each RUA, in the middle and final survey. The availability is summarized in Table E.
| no data | < 50% | 50% - 90% | > 90% | Number of RUAs | |
|---|---|---|---|---|---|
| Mid | 30 | 0 | 2 | 9 | 41 |
| Fin | 4 | 0 | 8 | 27 | 39 |
Table 5 presents the distribution of HICH. In the middle survey only 11 RUAs (27%) have data for the awareness of high blood cholesterol. In two of these RUAs (FIN-KUO and FIN-NKA) the proportion of missing data was high (11% and 10% respectively).
In the final survey only 4 (10%) RUAs (GER-AUR, GER-AUU, GER-ERF and NEZ-AUC) did not have data for the question. The proportion of missing data was high in 8 RUAs (range 10% - 41%). Exceptionally high proportions of missing data was in SWI-VAF (41%).
More than a 5% change in missing data between the middle and final survey was observed in SWE-GOT, where the proportion increased from 1% to 16%.
GER-AUR and GER-AUU have a question about awareness of high cholesterol in the middle and final survey but the RUAs have not provided any data for the item HICH.
All respondents
Table 6. present the distribution of CHDT. In the middle survey 10 RUAs (24%) do not have data for the dietary treatment of high cholesterol. In three RUAs (FIN-KUO, FIN-NKA and FIN-TUL) only the alternatives "if HICH = 2" (8) and "insufficient data" (9) are available and in all these RUAs the proportion of missing data is high (18% - 26%)
In the final survey 7 (18%) RUAs do not have data for the question. The proportion of missing data was high in 8 RUAs (range 11% - 36%). The proportion of missing data was exceptionally high in POL-WAR (36%). In three RUAs (FIN-KUO, FIN-NKA and FIN-TUL) only the alternatives "if HICH = 2" (8) and "insufficient data" (9) are available.
More than 5% change in missing data between middle and final survey was observed in FIN-NKA, where the proportion increased from 26% to 35% and in SWE-GOT were the proportion increased from 0% to 11%.
Specific instructions were given in the MONICA manual to code "uncertain", i.e. problematic or insufficient information, under CHDT: "if the person is following a special diet but he/she is not sure whether the diet is for cholesterol lowering purposes".
Respondents aware of their high cholesterol
Table 4 presents the availability of data on CHDT in each RUA in the middle and final survey. The availability is summarized in Table F.
| no data | < 50% | 50% - 90% | > 90% | Number of RUAs | |
|---|---|---|---|---|---|
| Mid | 33 | 0 | 2 | 6 | 41 |
| Fin | 7 | 4 | 6 | 22 | 39 |
For those who answer negatively to the HICH question, the response to the CHDT question should be negative. The response to CHDT question can, however, be positive even if the response is "no" or "insufficient data" in HICH, if the MCC has confirmed this as a reply to unresolved constraint violations. This happened only occasionally.
Table 7 presents the distribution of CHDT among those who are aware of their high cholesterol (HICH =1). In the final survey in CZE-CZE the proportion of "uncertain" information is 13%.
All respondents
Table 8. present the distribution of CHRX. In the middle survey 12 (29%) RUAs do not have data for the question about drug treatment of high cholesterol. In three RUAs (FIN-KUO, FIN-NKA and FIN-TUL) only the alternatives "if HICH = 2" (8) and "insufficient data" (9) are available and in all of these RUAs the proportion of missing data is high (range 18% - 26%).
In the final survey 6 RUAs (15%) do not have data for the question. The proportion of missing data is high in 6 (range 11% -36%) RUAs. The proportion of missing data was exceptionally high in POL-WAR (36%). In three RUAs (FIN-KUO, FIN-NKA and FIN-TUL) only the alternatives "if HICH = 2" (8) and "insufficient data" (9) are available.
More than a 5% change in missing data between the middle and final survey was observed in FIN-NKA where the proportion increased from 26% to 35% and in SWE-GOT where the proportion increased from 1% to 11%.
Special instructions were given in the MONICA manual to code "uncertain" under CHRX: "if the use of cholesterol lowering drugs is reported but the person in question is not sure whether these have been used during the last two weeks or he/she is not sure whether the drugs used were for lowering cholesterol".
In the middle survey BEL-CHA, BEL-GHE, DEN-GLO, GER-AUR, GER-AUU, ITA-BRI and UNK-BEL have a question about drug treatment of high cholesterol but they have not provided any data for the item CHRX. In the final survey GER-AUR, GER-AUU, FIN-KUO, FIN-NKA, FIN-TUL and NEZ-AUC have a question about drug treatment of high cholesterol but they have not provided any data for the item CHRX. The MDC has received data for item CHRX from RUS-NOI and RUS-NOC for the middle survey but MDC does not have information about the specific question used to derive these data.
Respondents aware of their high cholesterol
Table 4 presents the availability of data on CHRX in each RUA in the middle and final survey. The availability is summarized in Table G.
| no data | < 50% | 50% - 90% | > 90% | Number of RUAs | |
|---|---|---|---|---|---|
| Mid | 31 | 0 | 3 | 7 | 41 |
| Fin | 6 | 3 | 7 | 23 | 39 |
For those who answered negatively to the HICH question, the response to the CHRX question should be negative. The response to CHRX question can, however, be positive even if the response is "no" or "insufficient data" in HICH, if the MCC has confirmed this as a reply to unresolved constraint violations. This happened only in occasional cases.
Table 9 presents the distribution of CHRX among those who are aware of their high cholesterol (HICH =1). The proportion of "uncertain" information does not exceed 3% in the middle survey and 5% in the final survey.
Table 4 presents the availability of data on CHRECD in each RUA, in the middle and final survey. The availability is summarized in Table H.
| no data | < 50% | 50% - 90% | > 90% | Number of RUAs | |
|---|---|---|---|---|---|
| Mid | 31 | 0 | 1 | 9 | 41 |
| Fin | 4 | 0 | 8 | 27 | 39 |
Table 10 presents the distribution of CHRECD. In the middle survey 12 (29%) RUAs have data for the question "Have you had your blood cholesterol measured in the last year?". The proportion of missing data was high in two RUAs (range 19% -21%).
In the final survey 4 (10%) RUAs do not have data for the question. The proportion of missing data was high in 8 RUAs (10% - 21%).
More than a 5% change in missing data between the middle and final survey was observed in SWE-GOT where the proportion increased from 1% to 12%.
Tables 11, 12, 13 and 14 give the overall scores for the
quality of data for the items HICH, CHDT, CHRX and CHRECD respectively in each RUA. The
scores were defined as:
a) Questionnaire compliance score for each item:
| Score = | 0 | if no questionnaire was available in the MDC, no HICH/CHDT/CHRX/CHRECD question in the questionnaire, or the formulation of the question is significantly different from the standard format; |
| 1 | if an alternative formulation of the question was used, but it is considered of having only minor or no effect on prevalence estimates; | |
| 2 | for all other RUAs. |
b) Insufficient data score for each item:
| Score = | 0 | if the proportion of "insufficient" > 10%; |
| 1 | if the proportion of "insufficient" is 5-10%; | |
| 2 | for all other RUAs. |
c) "Uncertain" data score (for CHDT and CHRX only, see Tables 12 and 13):
| Score = | 0 | if the proportion of "uncertain" > 10% among persons aware of high cholesterol (HICH = 1); |
| 1 | if the proportion of "uncertain" is 5-10% among persons aware of high cholesterol (HICH = 1); | |
| 2 | for all other RUAs. |
d) Summary score for each item:
| Score = | 0 | if the Questionnaire compliance score, Insufficient data score or "Uncertain" data score is 0; |
| 1 | if the average of Questionnaire compliance score, Insufficient data score and "Uncertain" data score is 1 after rounding; | |
| 2 | if the average of Questionnaire compliance score, Insufficient data score and "Uncertain" data score is 2 after rounding. |
Table 15 has the overall summary score for all items. The overall summary score is defined as:
| Score = | 0 | if any of the item summary scores is 0; |
| 1 | if all item summary scores are over 0 AND at least one item summary score is less than 2; | |
| 2 | if all item summary scores are 2. |
The data for awareness and treatment of high cholesterol were collected in the middle and final surveys. Because the data for the initial survey are not available and in the middle survey there are only a few RUAs which have provided acceptable data for the analysis, these data cannot be used for trend analysis but can be used for cross-sectional analysis.
For item HICH the most common deviation from the standard MONICA format was omission of the expression "told by a doctor or other health worker". This can produce biases in both directions because the answer could be based on subjective feeling. In the middle survey 9 (22%) RUAs and in the final survey 27 (69%) RUAs have data which can be used for the cross-sectional analysis of awareness of high cholesterol.
Also for the item CHDT the most common source of bias was omission of the expression "prescribed by a doctor or other health worker". This can cause a bias because we cannot be sure if the diet was specifically to lower cholesterol. In the question CHDT the time period was the present time. In the AUS-PER final survey, they used the time period "in the last month"; this difference probably has only minor effects in the results, because the proportion of people who had stopped the diet during the last month, should be reasonable small. In middle survey 7 (17%) RUAs and in the final survey 25 (64%) RUAs have data which can be used for cross-sectional analysis of dietary treatment of high cholesterol.
Medical treatment of high cholesterol was asked by item CHRX. Omission of the expression "prescribed by a doctor or other health worker" was the most common deviation from the standard MONICA format with the use of a different time period. Both of these deviations may not cause any major deviations in the results, because the most people taking medication to lower cholesterol use prescribed medicines. It is also not likely that a person using drugs a month ago would have stopped in within the last two weeks. In the middle survey 7 (17%) RUAs and in the final survey 29 (74%) RUAs have data which can be used for cross-sectional analysis of drug treatment of high cholesterol.
The question of last cholesterol measurement (CHRECD) was one that had least deviation. All used questions can be considered equivalent with standard MONICA format. In the middle survey 9 (22%) RUAs and in the final survey 28 (72%) RUAs have data which can be used for cross-sectional analysis of the last measurement of cholesterol.
The data on all four questions related to the treatment of high cholesterol are usable in 5 (12%) RUAs in the middle survey and in 21 (54%) RUAs in the final survey.
The following list includes only those RUAs with specific findings or exceptional background information relevant for the use of data and the RUAs for which additional clarification is expected.
AUS-NEW
AUS-PER
BEL-CHA and BEL-GHE
CAN-HAL
CHN-BEI
CZE-CZE
DEN-GLO
FIN-KUO, FIN-NKA and FIN-TUL
FRA-LIL
FRA-STR
FRA-TOU
GER-AUR and GER-AUU
GER-BER
GER-BRE
GER-COT
GER-EGE
GER-ERF
GER-HAC
GER-KMS
HUN-BUD
HUN-PEC
ICE-ICE
ITA-BRI
ITA-FRI
LTU-KAU
NEZ-AUC
POL-TAR
POL-WAR
RUS-MOC
RUS-MOI
RUS-NOC
RUS-NOI
SPA-CAT
SWE-GOT
SWE-NSW
SWI-TIC
SWI-VAF
UNK-BEL
UNK-GLA
USA-STA
YUG-NOS