Objectives
and general characteristics 
PRESENTATION
Eduard
Rius i Pey, Ministry of Health
Our health system, like that of the majority of countries in our area, finds itself confronted with the challenge of being able to meet increasing demands and needs of the population with limited resources and at the same time, offer efficient, high quality health services that contribute to improving the health of all citizens.
In order to face up to this situation we must base ourselves on adequate organisation of the health system, as well as on powerful instruments for planning and managing the services provided, while always bearing in mind that the overall efficiency of the system is largely dependent on the contributions made by each professional, who is, after all, in the best position to be able to improve this effectiveness.
Whether it be professionals at the moment of making clinical decisions, or health care service planners and managers, adequate information is the one absolute necessity they all have in common.
Health care information is one of the basic elements for making the majority of decisions in the system. This includes social, economic and demographic information as well as data on the resources used in the health system, even including information on the activity and morbidity associated with the health care network.
In the area of hospital care this information is available in the register of the Minimum Basic Data Set for Hospital Discharges (CMBDAH) which is the basis for analysing the suitability and quality of the services provided, accessibility, variations in clinical practice, the complexity index for each centre and the costs per disease.
Making all this information available has required considerable effort on a technical, human and economic scale by the hospital centres themselves as well as the health care administration. But there is no doubt that the usefulness of this tool means that its potential benefits more than compensate for the effort required. We now have an instrument, the CMBDAH register, which with utmost respect for regulations regarding confidentiality and use, is available to any managers, health care professionals and research workers who wish to consult it.
The Health Care Department and the Catalan Health Service are firmly committed to promoting this use as a way of advancing towards the goals that have been established and of improving and maintaining the quality of this information.
INTRODUCTION
The systematic register of morbidity and of the activity of hospital centers is an instrument of great importance for hospitals and health-care authorities, in that it makes it possible to obtain information on the pathology treated, the characteristics of the treatment provided and its evolution over time. Consequently, these data are vital for the management of centers, for planning and evaluation and for defining the purchase of services.
In accordance with the order of November 23, 1990, "All public and private health-care centers and establishments located in Catalonia are obliged to draw up the minimum basic data set for hospital discharges (CMBDAH) for all those patients whose treatment has produced at least one overnight stay. Such data are to be sent regularly to the Department of Health and Social Security."
Since the transfer of the management of the CMBDAH Register to the Catalan Health Service (SCS) in 1993, the efforts made by both the hospitals and the Administration have brought about an improvement in the quality of the data and also made them more accessible.
With the aim of making this information available to the whole health-care system, the publication of "health-care activity reports" began in 1994. It was within this editorial framework that the CMBDAH series got underway with Discharges from acute-care hospitals in Catalonia, 1993.
In recent years, two key developments have taken place. On the one hand, there has been a change in the health-care approach, in the sense that certain procedures traditionally involving standard hospital stays have gradually been included in the ambulatory system. On the other hand, a new payment system has gone into effect (Decree 197/1997, of July 22), which determines the contracting of health-care services within the scope of the Catalan Health Service.
The growing need for information regarding not only health-care processes now being carried out within the ambulatory system but also those involving sub-acute patients in specialized psychiatric hospitals has prompted the systematic compiling of such data by the CMBDAH.
For this reason, the modification of the 1996 Instruction Manual for Reporting to the CMBDAH Register issues the following criteria:
"The CMBDAH must be notified of all hospital discharges of acute patients, including those involving major ambulatory surgery and day hospitals, all centers, whether public or private, located in Catalonia."
The implantation of the new payment system in the centers belonging to the Hospital Network for Public Use (XHUP) has contributed to more comprehensive, better-quality information. This is because part of the payment for the health-care process takes into account the complexity of the pathology treated, which is determined on the basis of the information provided to the CMBDAH. It should be made clear, however, that this is not analyzed in this report.
The information provided by the CMBDAH Register is at the disposal of managers, health-care professionals and researchers who may need it, with the utmost respect for confidentiality and proper use at all times. Both the Department and the Service wish to encourage such use in the belief that this is the best way of achieving the objectives they have established and of improving and maintaining the quality of the Register.
CMBDAH as a hospital management tool for the systematic compiling of information on the morbidity dealt with in these centers. Here we resume the publication of "Health-care activity reports" with the document Discharges from acute-care hospitals in Catalonia 1996-1999. Our intention is to continue making the information provided to the CMBDAH available to the entire health-care system.
Population-based registers make it possible to analyze the differences in the patterns of use of health-care services according to place of residence. In order to carry out this analysis, it is necessary to have good coverage of these registers and to bear in mind the limitations resulting from the lack of comprehensive data for certain pathologies or age groups (such as deliveries in private hospitals, for example). We can now assure our readers and colleagues that the CMBDAH Register has attained a sufficient level of coverage to begin population-based analyses that will be most useful for the planning and evaluation of objectives involving health care and service.
THE
CMBDAH REGISTER
Objectives and general characteristics
The fundamental objective of the CMBDAH Register is to create a comprehensive and valid data base on morbidity and hospital activity which can be used to understand the pathologies dealt with in the centers, for health-care planning, for the evaluation of resources and for the purchase of services.
The Register presents the data provided by the CMBDAH, which have been coded according to pre-established criteria in order to make them compatible and comparable with other information systems.
The criteria employed in the codification of the sociodemographic, administrative and perinatal variables have been based on the Instruction Manual for Reporting to the CMBDAH Register for 1996. For the clinical variables, the International Classification of Diseases, 9th Revision, Clinical Modification (ICD·9·CM) has been used.
During the 1996-1999 period, the ICD has been updated twice. Basically, these modifications have been made to give greater specificity to the codes and do not affect the results of the analysis for the year in which this report is presented, since the data are analyzed by code grouping.
Organization and operation
Every three months, the hospitals send the data pertaining to their activity to the CMBDAH Register either on diskette or by email.
Once received, the data are validated in accordance with the criteria presented in the section on quality control, and each hospital is sent the summary of the validation. At the end of the year, the hospital receives a report on its activity, and how it compares with other hospitals of similar characteristics.
The data on conventional hospitalization and CMA are sent annually to the Ministry of Health and Consumption so that they can be included in the national CMBDAH Register.
The CMBDAH is also a source of information for external users and must reply to requests received from other fields. In all cases, data can only be released in accordance with current regulations regarding confidentiality and use of information.
Since the inclusion of the activity of major ambulatory surgery (CMA), day hospital (HdD) and specialized psychiatric hospitals in the CMBDAH, the activity reported to the CMBDAH has been classified into the following types:
• Conventional hospitalizationDuring 1999, the CMBDAH Register received data from 79 acute-care hospitals (63 of which belong to the Hospital Network for Public Use (XHUP) and 16 of which do not) and 11 specialized psychiatric hospitals (ANNEX 1).
During the 1996-1999 period, the number of hospitals reporting to the CMBDAH has varied, with respect both to those who belong to the XHUP and those who do not (TABLE 1).
TABLE 1The difference in the number of XHUP hospitals between 1996 and 1997 (five fewer) is due to the fact that two centers belonging to the XHUP ceased acute-care activity and became social health-care centers; and three dropped their affiliation with the XHUP, even though they continued to provide acute care. On the other hand, a new center joined the CMBDAH, which did not belong to the XHUP.
In 1999, yet another new center joined that did not belong to the XHUP.
The information contained in the Register represents 100% of the discharges from the XHUP and one third of the activity of hospitals not belonging to the XHUP.
During the 1996-1999 period, the total activity reported to the CMBDAH has risen 22.8% (TABLE 2). This increase has taken place in all categories, but mainly in the activity corresponding to CMA (a rise of 246.9%) and HdD (a rise of 350.3%). Such spectacular growth is explained, on the one hand, by the increase of exhaustive information provided by the Register and, on the other, by a genuine increase in activity. Conventional hospitalization has undergone more moderate growth (an increase of 5.4%) while psychiatric sub-acute care has gone up 9.0%. With regard to the latter, it should be pointed out that the data corresponding to 1999 are not comprehensive owing to the lack of information provided by one specialized psychiatric hospital.
These changes, both qualitative and quantitative, in the Register's coverage should be kept in mind when comparing information from different years.
Internal validation
An internal validation is carried out on the data received in order to establish the quality of the information, to detect possible errors in each of the variables and to check the coherence between variables. This validation follows the criteria established in the Instruction Manual for Reporting to the CMBDAH Register and in accordance with the coding regulations of the ICD·9·CM.
During the internal validation process, two new variables are created on the basis of the original variables: the age of the patient (based on date of birth and date of admission) and the length of stay (based on date of admission and date of discharge).
It goes on to show the validity of the variables corresponding to conventional hospitalization and
CMA in 1999. In general, the discharge, sociodemographic and administrative identifying variables have a high level of validity. The validity of the clinical variables has improved considerably since 1995 (TABLE 3).
DESCRIPTIVE ANALYSIS OF THE CMBDAH REGISTER
The CMBDAH Register compiles the data recorded by each hospital relating to conventional hospitalization, major ambulatory surgery (CMA), day hospital (HdD) and treatment of psychiatric sub-acute patients.
This report summarizes the descriptive analysis of the 1999 CMBDAH Register and compares it with that of 1996, 1997 and 1998, with the aim of assessing the evolution of certain indicators.
• Conventional hospitalization together with CMA
Data for conventional hospitalization are analyzed together with those of CMA because major surgical procedures, which tend to be dealt with on an ambulatory basis, may at times require hospital admission. This depends on the characteristics of the patient (co-morbidity, sociodemographic conditions) or organizational decisions taken within the center (linked to the dispersion of the reference population). Given that one of the objectives of the CMBDAH is to analyze hospital morbidity, a joint analysis must be made.
The data corresponding to day hospitals and specialized psychiatric hospitals are analyzed separately, since they involve types of activity which differ significantly with respect both to each another and to the block of conventional hospitalization and CMA.
The definitions of the three basic concepts used in this report are as follows:
• Discharge: the situation of the patient upon conclusion of the period of hospitalization.These concepts will also be used when we refer to the day hospital (HdD), although instead of speaking of discharges we will use the term episodes, since this type of activity does not involve any period of hospitalization.
In the tables presenting the variables of age, sex or length of stay, where one or more of these is non-valid, discharges are considered to be null and void.
The remainder of the variables considered non-valid has been grouped under the category "unknown".
In the tables, percentages lower than 0.05% are given as "0.0". A complete absence of recorded cases is given as "-".
Discharges and patients
The number of patients is calculated on the basis of the hospital code and the medical record number. The medical record number makes it possible to identify those patients who have been treated more than once in the same hospital. However, it should be noted that the data compiled in the Register do not reveal whether a patient has been treated in different hospitals. This explains why the number of patients may be slightly overestimated and, consequently, the average number of discharges per patient underestimated.
The total number of discharges reported to the CMBDAH Register in 1999 was 747,482. These discharges corresponded to 608,560 patients. The average number of discharges per patient was 1.23. The average number of discharges for patients admitted more than once was 2.48. These patients (15.5% of the total) accounted for 31.2% of the total number of discharges.
The average number of discharges per patient shows differences according to sex (1.26 in men and 1.20 in women) and age group (FIGURE 1).
FIGURE 1The number of patients and the average number of discharges per year are shown in TABLE 4. As can be seen, the number of patients has grown, especially as regards patients with multiple discharges,
Age is calculated from two original variables: date of birth and date of admission. Because of the non-validity of one of the two original variables, the age variable was non-valid for 0.04% of the discharges.
The sex variable was non-valid for 0.02% of the discharges.
Of all discharges, 362,220 (48.5%) were men and 384,649 (51.5%) were women. During the 1996-1999 period, these proportions were similar. Nonetheless, there has been a slight increase in the proportion of women (51.0% in 1996).
The average age was 51.3 years (51.7 years for men and 51.0 years for women). TABLE 5 shows that, during the study period, the women were always younger than the men were and the average age went up each year for both sexes.
TABLE 5The distribution of discharges by age group and sex revealed widely varying results (TABLE 6).
Note: Hospitalization rate: number of discharges per 1,000 inhabitants
The discharges of women ranging in age from 25 to 34 accounted for 17.0% of the female discharges and 8.8% of all discharges.
Patients of both sexes over 64 years of age made up 38.5% of all discharges (34.8% in 1996) and those under 5 years of age, 6.7% (7.2% in 1996). The age group with the highest male proportion was that of 1 to 14 years.
FIGURE 2 shows the percentage distribution by age and sex for the discharges of Catalan residents recorded in the 1999 CMBDAH Register, and the Catalan population according to the 1996 census. The hospitalization rate has been calculated using these data (TABLE 6).
FIGURE 2The place of residence variable includes the codes for the province, town, district (in the case of residents of the city of Barcelona) and country (in the case of foreigners).
The degree of non-validity for this variable (14.2%) was considerably lower than in 1996 (1 7.2%).
Errors were attributable to the information relating to the municipal district of patients residing in the city of Barcelona.
If this factor is discounted, the residence code makes it possible to determine the town of 97.1% of discharges (95.9% in 1996).
The information provided by this variable makes it possible to establish the territorial distribution of discharges by health-care region and by health-care sector of residence.
On the basis of the province code, it is possible to assign certain discharges to the relevant health-care region, even when the town information was not valid. This has meant the assignation of the region of residence for 0.2% of discharges that had not made clear their town of residence. This assignation has been made for patients residing in the health-care regions of Lleida and Girona.
On the basis of the town code, the health-care sector of residence has been assigned to each discharge.
As for discharges of residents of the city of Barcelona, where the assignation requires knowledge of the municipal district, and in view of the fact that this information has yet to be exhaustively compiled, assignation of the health-care sector was not possible for all Barcelona residents. For this reason, all sectors of Barcelona have been treated together.
Of the total of 747,482 discharges, it was possible to assign the health-care region of residence to 710,129 (95.0%). As for the remainder of discharges, 16,077 (2.2%) resided outside Catalonia, while the place of residence was unknown for 21,276 discharges (2.8%).
Of the 710,129 discharges involving residents of Catalonia, 597,160 (84.1%) were treated in hospitals in their own health-care region of residence (84.0% in 1996) while 112,969 (15.9%) were treated in other regions. Of these discharges, 65,106 (9.2%) were residents of the health-care regions of Barcelona Ciutat, Costa de Ponent and Barcelona Nord i Maresme and were treated in one of these neighboring regions (9.3% in 1996). The remaining 47,863 discharges (6.7%) corresponded to movement between other health-care regions.
As regards discharges for whom residence is recorded as being outside Catalonia (TABLE 7), 47.7% were from hospitals of the Barcelona Ciutat health-care region and 17.4% from hospitals of the Lleida health-care region, most of whom (2,229 discharges) were residents of the province of Huesca. In absolute terms, the hospitals of the health-care region of Barcelona Ciutat produced the highest number of discharges of people standardized hospitalization rates have also been calculated, according to the direct method, using the population of Catalonia as the standard (TABLE 8). With respect both to health-care region and sector, differences have been seen in the four indicators calculated. Some of the lowest rates have been found in sectors where the population is most elderly and vice versa (TABLE 8).
Contrary to what one would expect, the variation in standardized rates was greater than in gross rates.
FIGURE 3 shows the standardized hospitalization rates of the discharges financed by the SCS, by health-care sector of residence. For the purpose of comparison, it also shows the rate for the whole of Catalonia and the variation coefficient weighted by population. Of the entire group of sectors, 25 were found within the limits defined by the variation coefficient, 9 plus Barcelona City which was treated as a single sector were below it and the remaining 11 sectors were above it.
FIGURE 3To evaluate the differences in hospitalization rates by health-care sector of the discharges financed by the SCS, one should bear in mind that publicly financed hospital health care in a territory is conditioned by the offer of other types of complementary health care coverage.
More frequent in urban areas with high socioeconomic levels, the offer of private health care coverage in free-choice insurance companies can be accompanied by relatively low public hospitalization rates.
In certain rural areas, where low population density and good communication cannot justify the presence of a hospital, primary attention takes on a substitute role in certain lines of attention. In this case, the hospitalization rates can be low.
From the viewpoint of health-care policy, the presence of a hospital is justified in areas of low density of population where communication is difficult, for example, in a mountainous region. In such cases, hospitalization rates are higher than average because the offer of attention provided by the close proximity of a hospital, no matter how small it may be, increases the demand.
The current situation caused by an aging population, in which the proportion of elderly, multiple-pathology patients is on the rise, causes the frequency of admission of these patients to depend to a large extent on the social health-care resources available in the area.
The source of payment variable records the entity or institution that paid for the sick person's hospitalization. Of all discharges, 0.05% were non-valid in terms of this variable.
84.7% of all discharges recorded in the Register were financed by the SCS, a proportion which rose to 94.4% if only the discharges from XHUP hospitals are analyzed. The number of discharges financed by the SCS in hospitals not belonging to the XHUP and which report to the CMBDAH Register was 7,434, a figure notably higher than the 1,241 reported in 1996. This increase was due to the activity of hospitals that in recent years have ceased to belong to the XHUP.
Of the 15,178 discharges paid for by private financing (2.0% of all discharges and 13.3% of the
The admission status variable was non-valid for 0.1% of discharges.
The breakdown of total discharges by status reveals that 48.4% were planned and 51.6% were emergencies. This distribution was similar in 1996-1999. Despite the large growth of programmed activity by CMA, the number of emergency admissions also grew in similar proportion.
With regard to the discharge status variable, 0.4% of the discharges were non-valid. 93.5% of discharged patients went home (TABLE 10). The 22,518 deaths constituted 40.1% of all deaths in Catalonia during 1999. This proportion was higher to that of 1996, which was 37.2%.
TABLE 10Length of stay is a variable calculated on the basis of the date of admission and the date of discharge. 0.03% of all discharges were not valid for the calculation of length of stay (this percentage includes stays longer than 6 months).
Average length of stay presents a very wide range of variation in relation to other variables such as age, sex, diagnosis or source of payment, among others.
In 1999, the average length of stay for all discharges was 6.3 days (FIGURE 5), while in 1996 it was 7.4 days. This decrease can be attributed to a large extent to improved hospital efficiency, but the inclusion of CMA is also an important contributing factor.
FIGURE 5In 1999, the discharges financed by the SCS were preceded by an average stay of 6.5 days while those that were non-financed lasted 5.1 days (7.7 days and 5.7 days in 1996, respectively). The shorter average length of stay preceding discharges not financed by the SCS is basically explained by the lower degree of complexity of the patients treated.
The average length of stay for men was 6.7 days, while for women it was 5.9 days. In general, there was a clear tendency for the average length of stay to increase with age, with the exception of infants under 1 year of age and women between 20 and 29 years of age (TABLE 11 and FIGURE 6). In almost all age groups, the average length of stay for women was shorter than for men, especially between the ages of 20 and 39, owing to the very high number of deliveries by women in this age group.
TABLE 11A high volume of hospitalization combined with a lengthy average stay meant that certain age groups represented very high percentages of the total number of days spent in hospital. This was the case of those over 64 years, who accounted for 38.5% of the discharges (TABLE 6) and accumulated 49.1% of all days spent in hospital (TABLE 11). In 1996, these figures were 34.8% of all discharges and 45.7% of all the days spent in hospital.
It is also important to take into consideration the significance of lengthy stays, because, although stays lasting longer than 30 days represented only 2.2% of discharges, they constituted 16.9% of the total number of days spent in hospital. In 1996, these figures accounted for 2.8% of all discharges and 18.2% of all days spent in hospital. The decrease of lengthy stays seen during the period of study would explain a quarter of the 1.1-day length-of-stay difference between 1996 and 1999.
The CMBDAH records the main diagnosis of each discharge and up to three further diagnoses, coded according to the ICD·9·CM.
The main diagnostic variable indicates the reason why a sick person was admitted to hospital.
The other diagnoses include all illnesses or complications detected
in the sick person which are not considered as being the main diagnosis; either already present at the time of admission or developed during the stay in hospital.
The percentage of non-valid discharges for the diagnostic variable was 0.9% of all discharges. Lack of specific information was the cause of non-validity in 0.4% of discharges. The term "non-specific diagnosis" involved those cases, where, although correct, the information failed to present the maximum detail possible.
In 0.4% of all discharges there was no recorded information on the main diagnosis; the variable was either left blank or entered as an unknown diagnosis (code 799.9). The other causes of non-validity were attributable to coding errors not included in the ICD·9·CM and inconsistencies in relation to age and/or sex (0.1%).
Accordingly, in 0.5% of all discharges, there was no recorded information on the main diagnosis. In 1996 this percentage was 1.1%.
64.5% of the discharges provided correct information regarding the first secondary diagnosis, while for the second the percentage was 43.2% and for the third 29.6%. Non-validity of these further diagnoses was due primarily to lack of specificity, which for the three secondary diagnoses was 0.1%. Non-validity as a result of error or inconsistency was 0.04%.
The average number of recorded diagnoses per discharge (main and other) was 2.37. In 1996 it was 2.12.
The main diagnosis has been analyzed according to two levels of classification:
Major ICD·9·CM diagnostic categories
The ICD·9·CM sets out more than 13,000 diagnostic codes in 17 categories, plus V code, which covers factors influencing health status and contacts with health services.
TABLE 12 shows the distribution of discharges by main diagnosis, in terms of these 18 categories.
TABLE 12Note: Main diagnostic unknown: main diagnosis not reported, erroneous or inconsistent with age and/or sex
The five major categories with the greatest number of discharges were those having to do with the circulatory, digestive and respiratory systems, diseases of the nervous system and sense organs and neoplasms. These categories altogether constituted 52.0% of all discharges.
During the 1996-1999 period, diseases of the circulatory, respiratory and digestive systems were the most frequent. Diseases of the nervous system and sense
organs showed highest growth (a rise of 32.6%) on account of increased CMA activity.
Although each group comprises very different diagnoses and patient typologies, it should be mentioned that the longest average stays were those involving mental disorders, neoplasms and conditions originating in the perinatal period. The shortest stays were for diseases of the nervous system and sense organs and complications of pregnancy, delivery and the puerperium (TABLE 12).
The diagnostic groups accumulating most days in hospital were diseases of the circulatory system, neoplasms, diseases of the respiratory system and injuries and poisoning, which constituted 51.5% of all stays.
Significant differences were seen with regard to the average age.
The highest percentages involved diseases of the circulatory system, of nervous system and sense organs and neoplasms. The lowest corresponded, predictably, to perinatal and congenital diseases, followed by deliveries and infectious diseases (TABLE 12).
There were also differences in the distribution of discharges by cause of admission in relation to the age and sex of the patient (TABLES 13 and 14).
TABLE 13Perinatal conditions and respiratory diseases were significant for members of both sexes under the age of 5. Circulatory problems were most frequent in women over 64 and men between 55 and 84. Differences by sex were most evident in the intermediate ages: in women, deliveries (15 to 44 years), neoplasms (45 to 54 years) and diseases of the musculoeskeletal system and connective tissue (55 to 64 years); and in men, injuries (5 to 34 years). Problems related to the digestive system were significant for both men and women of practically all age groups, but fundamentally for men between 35 and 54 years of age.
Diagnostic categories of the CCHPR
The Clinical Classifications for Health Care Policy Research (CCHPR) organize all the diagnostic codes into 259 diagnostic categories, using first and foremost a clinical criterion. These 259 categories are then broken down into 17 groups.
ANNEX 2 sets out the detailed codes that make up each of the diagnostic categories.
TABLE 15 shows the total number of discharges and the percentage distribution, average length of stay, average age, proportion of discharges among women and mortality rate for 1999, as well as the number of discharges and percentage distribution for 1996 for comparative purposes.
It should be pointed out that the categories showing greatest growth during the 1996-1999 period were cataracts, chronic obstructive pulmonary disease, varicose veins of lower extremities and congestive heart failure, non-hypertensive. Categories showing a proportionate drop included normal pregnancy and /or delivery, maintenance chemotherapy and radiotherapy, acute and chronic tonsillitis and hyperplasia of prostate.
The following are the most noteworthy characteristics of TABLE 15 for the most relevant categories, compared with those of 1996,1997 and 1998.
TABLE 15Notes: Not assigned: codes that may apply to more than one category. Main diagnosis unknown: main diagnosis not recorded, erroneous or inconsistent with age and/or sex.
The CMBDAH Register presents up to 4 diagnostic or therapeutic procedures, coded in accordance with the ICD·9·CM.
The first is the diagnostic or therapeutic procedure, which is carried out during admission of the patient and most directly related to the main diagnosis.
This variable was recorded in 75.0% of all discharges, of which 0.2% were not specified and 0.03% either erroneous or inconsistent with age and/or sex.
As for other procedures, the percentages of notification were 35.0% for the second, 12.8% for the third and 6.3% for the fourth. The average number of procedures recorded per discharge was 1.29 (1.16 in 1996).
As with the main diagnosis, each category level is presented in terms of two procedural types:
• Procedural categories of the Clinical Classifications for Health Care Policy Research (CCHPR) proposed by the Agency for Health Care Policy and Research (AHCPR) of the Department of Health and Human Services of the United States.
Major ICD·9·CM procedural categories
The ICD·9·CM breaks down the more than 4,000 procedural codes into 16 major categories.
TABLE 16 shows the distribution of discharges by first procedure in terms of these major categories.
TABLE 16Operations on the digestive system, operations on the musculoskeletal system, obstetrical procedures and operations on the eye accounted for 44.4% of the discharges for which the first procedure was recorded. During the 1996-1999 period, these procedural categories were always the most frequent, if one discounts the category of miscellaneous procedures, which rose from 15.3% in 1996 to 22.6% in 1999. In evaluating this growth, it should be kept in mind that the miscellaneous procedural category was made up almost entirely of non-surgical procedures.
Although each category comprises very different procedures and patient typologies, the longest average stays were the