Indicators of Health - Morbidity Indicators PDF

By Ashraf Hussain MBChB.PhD/COM.MED  Morbidity is defined as "any departure wether subjective or objective from the state of physiological well-being"  The term is used equivalent to sickness, illness, disability etc.  Morbidity Indicators used to describe health status in...

By Ashraf Hussain MBChB.PhD/COM.MED  Morbidity is defined as "any departure wether subjective or objective from the state of physiological well-being"  The term is used equivalent to sickness, illness, disability etc.  Morbidity Indicators used to describe health status in the community beside the mortality indicators.  Burden of diseases can not be described just by its virulence or mortality rates, life burden of the disease may be more crucial.  Therefore, morbidity indicators are used to supplement mortality data to describe the health status of a population. The value of morbidity data is summarized as follows: 1. They describe the extent and nature of the disease burden in the community, and thus assist in the establishment of priorities. 2. They usually provide more comprehensive and more accurate and clinically relevant information on patient characteristics, than can be obtained from mortality data, and are therefore essential for basic research. 3. They serve as starting point for aetiological studies, and thus play a crucial role in disease prevention. 4. They are needed for monitoring and evaluation of disease control activities. The following morbidity rates are used for assessing ill-health in the community 1. Incidence and prevalence 2. Notification rates 3. Attendance rates at out-patient departments, health centrer, etc. 4. Admission, readmission and discharge rates 5. Duration of stay in hospital, and 6. Spells of sickness or absence from work or school. Incidence rate refers only to 1. new cases 2. during a given period (usually one year) 3. in a specified population or "population at risk", unless other denominators are chosen. 4. it can also refer to new spells or episodes of disease arising in a given period of time, per 1000 population. For example, a person may suffer from common cold more than once a year.  Incidence rate must include the unit of time used.  It is not influenced by the duration of the disease.  The use of incidence is generally restricted to acute conditions.  incidence rate can be denoted as attack rate when the population is exposed to risk for a limited period of time such as during an epidemic.  The incidence rate, as a health indicator, represent the risk of occurrence of the disease and is useful for 1. Taking action to control disease, and for 2. Research into aetiology and pathogenesis, distribution of diseases, and efficacy of preventive and therapeutic measures 1. The term "disease prevalence" refers specifically to all current cases (old and new) existing at a given point in time, or over a period of time in a given population. 2. "the total number of all individuals who have an attribute or disease at a particular time (or during a particular period) divided by the population at risk of having the attribute or disease at this point in time or midway through the period “ 3. Prevalence is of two types : (a) Point prevalence (b) Period prevalence Prevalence depends upon 2 factors,  the incidence and duration of illness.  Given the assumption that the population is stable, and incidence and duration are unchanging, the relationship between incidence and prevalence can be expressed as : P= IxD = incidence x mean duration Example (for a stable condition)  Incidence = 10 cases per 1000 population per year  Mean duration of disease = 5 years  Prevalence = 10 x 5= 50 per 1000 population  So that the longer the duration of the disease, the greater its prevalence.  For example, tuberculosis has a high prevalence rate relative to incidence. This is because new cases of tuberculosis keep cropping up throughout the year, while the old ones may persist for months or years.  On the other hand, if the disease is acute and of short duration either because of rapid recovery or death, the prevalence rate will be relatively low compared with the incidence rate. In some diseases (e.g., food poisoning), the disease is so short-lived, there are no "old" cases.  The same is true of conditions which are rapidly fatal, such as some types of cancers.  In other words, decrease in prevalence may take place not only from a decrease in incidence, but also from a decrease of the duration of illness through either more rapid recovery or more rapid death.  When we see a change in prevalence from one time period to another, this can result from changes in incidence, changes in duration of disease or both. For example,  improvements in treatment may decrease the duration of illness and thereby decrease prevalence of a disease. But if  the treatment is such that by preventing death, and at the same time not producing recovery, may give rise to the apparently paradoxical effect of an increase in prevalence. Uses of prevalence  Prevalence helps to estimate the magnitude of health/ disease problems (Burden) in the community, and identify potential high-risk populations  Prevalence rates are especially useful for administrative and planning purposes, e.g., hospital beds, manpower needs, rehabilitation facilities, etc.  Notification of Diseases 1. Disease notification is a practice of reporting the occurrence of a specific disease or health-related condition to the appropriate and designated authority. 2. A notifiable disease is any disease that is required by law to be reported to government authorities.   3. Effective notification allows the authorities to monitor the disease, and provides early warning of possible outbreaks 4. A notifiable disease is one for which regular and timely information regarding individual cases is considered necessary for the prevention and control of the disease. 1. Its severity (potential for rapid mortality) 2. Its communicability/ Its potential to cause outbreaks 3. Significant risk of international spread 4. The socio-economic costs of its cases 5. Its preventability 6. Evidence that its pattern is changing 1. Notification data can include only a small portion of the total illness in the community 2. Atypical and subclinical cases escape notification e.g. Rubella Non paralytic polio etc. 3. Accuracy of notification is dependent upon availability of facilities for diagnosis 4. Often the disease is not reported because: a. Healthcare worker is not aware b. Intention to report a lower incidence to prove effective administration etc. In spite of mentioned limitations, 1. Notification provides valuable information about fluctuation in disease frequency 2. It also provides early warning about new occurrences or outbreaks of disease 3. It has become a valuable source of morbidity data i.e. the incidence and distribution of certain specified diseases which are notifiable. Always Notifiable  Smallpox  Poliomyelitis due to wild-type poliovirus  Human influenza caused by a new subtype  Severe acute respiratory syndrome (SARS) Other Potentially Notifiable Events  Cholera  Pneumonic plague  Yellow fever  Viral hemorrhagic fever Disability-adjusted life years (DALY) :  DALY is a measure of overall disease burden, expressed as a number of years lost due to ill-health, disability or early death.  It captures the population impact of important fatal and nonfatal disabling conditions through a single measure.   Disability-adjusted life years {DALYs) combines 1. years of lost life {YLL) - calculated from the number of deaths at each age multiplied by the expected remaining years of life according to a global standard life expectancy 2. years lost to disability {YLD) where the number of incident cases due to injury and illness is multiplied by the average duration of the disease and a weighting factor reflecting the severity of the disease on a scale from 0 {perfect health) to 1 (dead). 3. It is calculated by formula : DALY = YLL + YLD Nutritional status is a positive health indicator. indicators of health status. 1. anthropometric measurements of preschool children, e.g., weight and height, mid-arm circumference; 2. heights (and sometimes weights) of children at school entry; and 3. prevalence of low birth weight {less than 2.5 kg). The frequently used indicators of health care delivery are:  Doctor-population ratio  Doctor-nurse ratio  Population-bed ratio 1. proportion of infants who are "fully immunized“ against the 6 EPI diseases. 2. proportion of pregnant women who receive antenatal care, or have their deliveries supervised by a trained birth attendant.