CHAPTER 1 BASIC STATISTICAL DATA USED IN …

1 CHAPTER 1 KEY TERMSA utopsyAverage daily censusAverage length of stay (ALOS)Bed count dayBed turnover rateCensusConsultationDaily inpatient censusDeath rateDichotomous variablesDirect maternal deathDischarge daysFetal autopsy rateFetal deathFetal death rateFrequency distributionGross autopsy rateGross death rateHospital-acquired infectionHospital autopsy rateIndirect maternal deathInpatient bed occupancy rateInpatient service dayLength of stay (LOS)Maternal death rateNet autopsy rateNet death rateNewborn autopsy rateNewborn death rateOutpatientsPostoperative infection rateProportionRateRatioSurgical operationSurgical procedureTotal length of stayVariableLEARNING OBJECTIVESAt the conclusion of this CHAPTER , you should be able to:1.

2 Define key Define hospital rates and Calculate hospital measures of morbidity, mortality, and volume is often said that hospitals and other types of health care facilities are data richbut information poor. There are many types of databases within the facility, manycontained within the organization s information warehouse. Information ware-houses contain both clinical and financial information. It is the job of the healthinformation management professional to turn the data contained in these data -bases into information that can be used by physicians, administrators, and 7/23/07 2:43 PM Page 1 Jones and Bartlett Publishers.

3 NOT FOR SALE OR DISTRIBUTION interested parties. The health information management professional can becomean invaluable member of the health care team by providing data that are presentedin a meaningful way and by presenting data that have been analyzed to serve a spe-cific medical or clinical need. Some typical questions might be: What are the top 25 medical and top 10 surgical diagnosis-related groups(DRGs) for inpatient discharges from our facility? Which medical/surgical services admit the most patients? Is the average length of stay (ALOS) for these DRGs significantly different fromthe national ALOS for these DRGs?

4 How do our charges compare with national charges? How does our reim-bursement compare with our costs? What geographical area does the health care facility serve? How many patients by payer were admitted to the facility? What is the numberof inpatient service days by payer? What are the average charges by payer? How do lengths of stay (LOSs) compare by physician? How many patients acquired nosocomial infections?In the course of this text, we will answer these questions. We will learn how to pre-sent data in graphic form and how to use descriptive statistics to describe patientpopulations.

5 Our goal is to collect, analyze, and interpret clinical information forboth clinical and administrative health care decision makers. We will begin ourdiscussion of commonly reported hospital rates and hospital volume to Frequency DistributionsIn health care, we deal with vast quantities of clinical data . Because it is very dif-ficult to look at data in raw form, data are summarized into frequency distribu-tions. A frequency distributionshows the values that a variable can take and thenumber of observations associated with each value. A variableis a characteristicor property that can take on different values.

6 Height, weight, gender, and third-party payer are examples of example, suppose we are studying the variable patient LOS in the pedi-atric unit. To construct a frequency distribution, we first list all the values thatLOS can take, from the lowest observed value to the highest. We then enter thenumber of observations (frequencies) corresponding to a given LOS. Table il-lustrates what the resulting frequency distribution looks like. Notice that all val-ues for LOS between the lowest and highest are listed, even though there may notbe any observations for some of the values.

7 Each column of the distribution isproperly labeled, and the total is given in the bottom row. We can also display afrequency distribution by categories into which a variable may fall. Table showsa frequency distribution for the number of patients discharged from Critical2| CHAPTER 1: BASIC STATISTICAL data Used in Acute Care 7/23/07 2:43 PM Page 2 Jones and Bartlett Publishers. NOT FOR SALE OR DISTRIBUTIONCare Hospital by religion, a variable composed of categories. The proportion foreach category is also displayed in the table. The sum of the proportions for eachcategory is equal to We will examine frequency distributions in greater detailin CHAPTER , Proportions, and RatesVariables often have only two possible categories, such as alive or dead, or male orfemale.

8 Variables having only two possible categories are called , Proportions, and Rates|3 Table Distribution of Patient Lengthof Stay (LOS), Pediatric UnitLOS in DaysNo. of Patients1222304656611768593101 Total42 Table Distribution of Number ofPatients Discharged from Critical Care Hospital byReligion, July 20xxNumber 7/23/07 2:43 PM Page 3 Jones and Bartlett Publishers. NOT FOR SALE OR DISTRIBUTION frequency measures used with dichotomous variables are ratios, proportions, andrates. All three measures are based on the same formula:xratio, proportion, rate = 10nyIn this formula,xand yare the two quantities being compared, and xis dividedby read as 10 to the nthpower.

9 The size of 10nmay equal 1, 10, 100, 1000,or more, depending on the value ofn:100= 1101= 10102= 10 10 = 100103= 10 10 10 = 1000 Ratios and ProportionsA ratio is a comparison between two different things. In a ratio, the values of avariable (such as gender:x= female,y= male) are expressed so that xand yarecompletely independent of each other. For example, the gender of patients dis-charged from a hospital is compared as:In this example, the ratio represents the number of female discharges com-pared to the total number of male then would you calculate the female-to-male ratio for a hospital that dis-charged 457 women and 395 men during the month of July?

10 The procedure forcalculating a ratio is outlined in Exhibit proportion is a particular type of ratio. A proportionis a ratio in which xisa portion of the whole,x + y. In a proportion, the numerator is always includedin the denominator. Exhibit outlines the procedure for determining the pro-portion of hospital discharges for the month of July that was are a third type of frequency measure. In health care,ratesare often used tomeasure an event over time and are sometimes used as performance improvementmeasures. The BASIC formula for a rate isNumber of cases or events occurring during a given time period 10n Number of cases or population at risk during same time periodfemalex , or maley4| CHAPTER 1: BASIC STATISTICAL data Used in Acute Care 7/23/07 2:43 PM Page 4 Jones and Bartlett Publishers.