Rajakumar.M,
Manager-Medical Records,
Aravind Eye Care System.

Statistics are facts set down as figures. Preparing statistics involves the collection, analysis, interpretation, and presentation of facts as numbers. The hospital administrator and governing board use statistics to compare current operations with the past, and as a guide in planning for the future. Keeping up with current reporting needs will save a great deal of unnecessary work and will help in modify the collecting techniques so that information kept will be accurate and useful. Medical records are the primary sources of data used in compiling medical statistics.

Computation of Data:
There is increasing emphasis on standardization of health statistics for valid intra-hospital and inter-hospital comparisons and analysis. The percentages or rates, which the medical record technician is asked to compute, are defined below.

1.Death rate
Death rates can be computed for deaths occurring both before and after 48 hours of admission, and are often requested by reporting agencies. However, as an indicator of hospital care, it would probably be more useful to examine all deaths that occur regardless of how soon after admission the patient dies. The same concept can be applied to postoperative deaths, which are usually considered to be deaths that occur within 10 days following surgery. Here it would probably be more useful to examine the relationship between deaths and surgical operations by selected groups of patients operated on, rather than to lump all patients and kinds of operations together to compute a postoperative death rate.

2.Hospital Death Rate (gross death rate)
The proportion of inpatient hospitalizations that end in death, usually expressed as percentage the percentage is computed as follows:

Number of deaths of inpatients in a period       X 100
Number of discharges (including deaths)
in the same period

2a.Net Death Rate (institutional death rate):
The ratio of the total number of deaths occurring in the hospital, 48 hours or more after admission, for a period to the total number of discharges and deaths, 48 hours and over, for that period. The formula for figuring the percentage is

Deaths (including newborn) minus those under 48 hours for a period    X 100
Total number of discharges (including deaths and newborn) minus
deaths less than 48 hours for the period.

2b.Anesthesia Death Rate:
The ratio of anesthesia deaths caused by anesthetic agents for a period to the number of anesthetics administered for the period. Since anesthesia deaths occur infrequently, this rate will usually be computed on an annual basis. An anesthetic death is defined as a death that takes place while the patient is under anesthesia or which is caused by anesthetics or other agents used by an anesthetist or anesthesiologist in the practice of his profession.

3.Infection rates:
Hospital by laws should specify that there be a hospital- wide committee charged with the responsibility to investigate, control, and prevent infections. The primary purpose of evaluating infections is to determine the cause so that repetition may be avoided. Medical judgment is needed to establish the incidence of infections and the proper control measures to be taken.

3.a Postoperative Infection Rate
The ratio of all infections in clean surgical cases to the number of operations. The postoperative infection rate may also be required on statistical reports. If a wound infection rate is needed, it must be specified if this is to be computed out of all operations or out of all clean operations.

Number of infections in clean surgical cases for a period     X100
Number of surgical operations for the period

4. Length of stay calculations:
The length of stay (for one inpatient) is the number of calendar days from admission to discharge. To compute a patients length of stay, the date of admission is subtracted from the date of discharge when the patient is admitted and discharged in the same month.

4.a Average length of stay
The average length of stay (average duration of hospitalization, average stay) is the average length of hospitalization of inpatients discharged during the period under consideration. The formula for computing the average duration of inpatient hospitalization is

Total length of stay (discharge days)
Total discharges

4.b Average Daily Inpatient Census
The average Daily Inpatient Census (average daily census) records the average number of inpatients present each day for a given period of time. To arrive at the average number of inpatients in the hospital, the total inpatient service days for the period must first be determined. The formula to obtain the average daily inpatient census for a whole hospital is

The formula to obtain the average daily inpatient census for a whole hospital is

=  Total inpatient service days for a period
Total number of days in the period

5. Inpatient Bed Occupancy Ratio
The inpatient bed occupancy ratio can be computed at any specified point of time or for any specified day. To compute the percentage for a specified day, the inpatient service days for that day is multiplied by 100 and divided by the inpatient bed count for that day. To obtain the inpatient bed occupancy ratio as a daily average in a longer period, the formula is

To obtain the inpatient bed occupancy ratio as a daily average in a longer period, the formula is

=  Total inpatient service days for a period  X 100
  Total inpatient bed count days (X)
number of days in the period

Generation of reports:
The daily, monthly analysis report concerning the professional care rendered to patients may indicate the number of patients registered newly as out patients, and the number of patients registered as revisit patients. This will include reports of admissions, discharges, number of surgeries performed and, the number of patients occupied as inpatients on a given day or month. This report may be combined with a comparative report of the previous year, the same day and same month. If this is done on a routine manner the necessary additional data can be compiled on a daily monthly and yearly basis. Monthly analysis and comparative reports are important to the hospital administration and the governing board for future planning and control of activities.

Vital Records
Medical records are the source documents for much of the information needed for birth, death and fetal death registration certificate, which are used for the States vital record system. The MRD has the responsibility for preparing birth and Fetal death certificates and for transmitting the information to the Registar of vital records.