Length of stay (LOS) is the duration of a single episode of
hospital
A hospital is a health care institution providing patient treatment with specialized health science and auxiliary healthcare staff and medical equipment. The best-known type of hospital is the general hospital, which typically has an emerge ...
ization.
Inpatient
A patient is any recipient of health care services that are performed by healthcare professionals. The patient is most often ill or injured and in need of treatment by a physician, nurse, optometrist, dentist, veterinarian, or other health ca ...
days are calculated by subtracting day of admission from day of
discharge.
Analysis
A common statistic associated with length of stay is the average length of stay (ALOS), a mean calculated by dividing the sum of inpatient days by the number of
patient
A patient is any recipient of health care services that are performed by healthcare professionals. The patient is most often ill or injured and in need of treatment by a physician, nurse, optometrist, dentist, veterinarian, or other health c ...
s admissions with the same
diagnosis-related group
Diagnosis-related group (DRG) is a system to classify hospital cases into one of originally 467 groups, with the last group (coded as 470 through v24, 999 thereafter) being "Ungroupable". This system of classification was developed as a collaborat ...
classification. A variation in the calculation of ALOS can be to consider only length of stay during the period under analysis.
Length of stay is typically highly
skewed
In probability theory and statistics, skewness is a measure of the asymmetry of the probability distribution of a real-valued random variable about its mean. The skewness value can be positive, zero, negative, or undefined.
For a unimoda ...
, so statistical approaches taking that into account are recommended.
While the mean length of stay is useful from the point of view of costs, it may be a poor statistic in terms of representing a typical length of stay; the
median
In statistics and probability theory, the median is the value separating the higher half from the lower half of a data sample, a population, or a probability distribution. For a data set, it may be thought of as "the middle" value. The basic fe ...
may be preferred.
It is useful to be able to predict an individual's expected length of stay or to model length of stay to determine factors that affect it. Various analyses have sought to model length of stay in different condition contexts. This has usually been done with
regression model
In statistical modeling, regression analysis is a set of statistical processes for estimating the relationships between a dependent variable (often called the 'outcome' or 'response' variable, or a 'label' in machine learning parlance) and one ...
s, but
Markov chain
A Markov chain or Markov process is a stochastic model describing a sequence of possible events in which the probability of each event depends only on the state attained in the previous event. Informally, this may be thought of as, "What happe ...
methods have also been applied.
Within regression approaches, linear, log-normal and logistic regression approaches have been applied, but have been criticised by other researchers.
Carter & Potts (2014) instead recommend use of
negative binomial
In probability theory and statistics, the negative binomial distribution is a discrete probability distribution that models the number of failures in a sequence of independent and identically distributed Bernoulli trials before a specified (non-r ...
regression.
Quality metric
Length of stay is commonly used as a quality metric.
The
prospective payment system A prospective payment system (PPS) is a term used to refer to several payment methodologies for which means of determining insurance reimbursement is based on a predetermined payment regardless of the intensity of the actual service provided.
It in ...
in U.S.
Medicare for reimbursing
hospital care promotes shorter length of stay by paying the same amount for procedures, regardless of days spent in the hospital.
Additionally, length of stay in hospital can be linked to additional quality metrics such as patient satisfaction with health professionals, reduction in hospital readmissions, and even mortality. Discharge planning processes can be effective in reducing a patients length of stay in hospital. For example, for older people admitted with a medical condition, discharge planning has been shown to improve satisfaction, reduce the overall length of stay, and within 3-month period reduce the likelihood of readmission.
Non-health usages
The term "average length of stay" (ALOS) is also applicable to other industries, e.g. entertainment, event marketing, trade show and leisure. ALOS is used to determine the length of time an attendee is expected to spend on a site or in a venue and is part of the calculation used to determine the gross sales potential for selling space to vendors etc. and affects everything from parking to sanitation, staffing and food and beverage. Almost all operational aspects can be altered by an attendee's ALOS.
References
{{DEFAULTSORT:Length Of Stay
Medical terminology