Point prevalence

Disease refers to the number of cases existing in a population. Point-prevalence identifies the pre alcncc estimated at a given time, e.g.. the number of workers with abnormal chest films from a surv ey. Prevalence is computed as the number of cases divided by the number of study subjects at a given point in time. 

Efficacy. A pivotal study by Hurt et al. (1997) established the efficacy and safety of bupropion SRfor treatment of nicotine dependence, which led to its approval for this indication by the FDA in 1998. This study was a 7-week, double-blind, placebo-controUed, multicenter trial of three doses of bupropion SR (100 mg/day, 150 mg/day, or 300 mg/day in twice daily dosing). Patients were 6l5 cigarette smokers who smoked at least 15 cigarettes/day. The medication was administered in combination with weekly individual cessation counseling. End-of-trial 7-day point prevalence cessation rates were 19.0% for placebo and 28.8%, 38.6%, and 44.2% for the 100 mg/day, 150 mg/day, and 300 mg/day bupropion doses, respectively. At 1-year follow-up, cessation rates were 12.4% for placebo and 19.6%, 22.9%, and 23.1% for the 100 mg/day,... 

Prevalence rates for a variety of different types of pain have been described. The annual incidence of moderate-intensity back pain is 10% to 15% in the adult population with a point prevalence of 15% to 30%.3 Migraine affects more than 25 million Americans, and 90% of Americans report some other types of headaches (e.g., tension or sinus) each year.4 Pain resulting from fibromyalgia affects 4 million Americans.5 Cancer is commonly associated with both acute and chronic pain, and about 70% of those diagnosed with cancer will experience significant pain.6... 

Cluster headache disorders are the most uncommon and severe primary headache syndromes.9 The estimated point prevalence is less than 1%. Unlike migraine and TTH, cluster headaches occur more frequently in men. Onset commonly occurs prior to age 30.6 A genetic predisposition seems apparent, although affected individuals often provide a history of tobacco use and alcohol abuse.6 Attacks consist of debilitating, unilateral head pains that occur in series lasting up to months at a time, but that remit over months to years between occurrences. In rare instances, cluster headache can be a chronic disorder without remissions.4... 

Author, date Type of study Country No. of subjects Point prevalence Definition... 

Walsh TR, Weeks J, Livermore DM et al (2011) Dissemination of NDM-1 positive bacteria in the New Delhi environment and its implications for human health an environmental point prevalence study. Lancet Infect Dis ll(5) 355-362... 

Table 2 summarizes Hfetime, 12-month, 6-month and point prevalence findings for anxiety disorders across major commimity studies that have been conducted since the introduction of the DSM-III in 1980. Table 2 in addition provides information about diagnostic criteria, instriunents used, and sample... 

Table 2 also indicates that the prevalence estimates for 12-month, 6-month and point prevalences are lower when compared to the Ufetime estimates. This can be seen as one indicator of the fluctuating character of anxiety disorders. As discussed above, variation across studies is probably mainly due to differences in study characteristics. OveraU, the 12-month prevalence rates for any anxiety disorder result in an estimated median of 11%, indicating that 1 in 10 people were affected by an anxiety disorder in the year preceding the assessment. 

The primary indication for antidepressant agents is the treatment of MDD. Major depression, with a lifetime prevalence of around 17% in the USA and a point prevalence of 5%, is associated with substantial morbidity and mortality. MDD represents one of the most common causes of disability in the developed world. In addition, major depression is commonly associated with a variety of medical conditions—from chronic pain to coronary artery disease. When depression coexists with other medical conditions, the patient s disease burden increases, and the quality of life—and often the prognosis for effective treatment—decreases significantly. 

Major depression is one of the most common psychiatric disorders. At any given moment, about 5-6% of the population is depressed (point prevalence), and an estimated 10% of people may become depressed during their lives (lifetime prevalence). The symptoms of depression are often subtle and unrecognized both by patients and by physicians. Patients with vague complaints that resist explanation as manifestations of somatic disorders and those who might be simplistically described as "neurotic" should be suspected of being depressed. 

One approach to this issue would be to study the point prevalence of TD in various countries. Combining the results of published studies from Asian countries yields a prevalence of 11%, versus 28% from North American studies and 21% from European studies (Gray and Pi 1998). However, such an approach does not take into account differences in patient populations, methods of assessment, or definition of TD. 

As goiter declines, iodine intake has to increase to maintain the same impact. Progressing from the left to the right of Table 80.4, it is possible to estimate what happens when prevalence of goiter declines. For example, at 63% prevalence of goiter (second row, first column) urinary iodine has to increase by 1.2 pg/1 (fifth row, first column) to produce a decline of 1% point prevalence. At 10% prevalence (first row, last column) the increase in urinary iodine excretion associated... 

The point prevalence includes only subjects with actual OCD. Since OCD is often a chronically relapsing disease, the point prevalence is therefore less informative than the period prevalence. However, the accuracy of recall will decrease with time, because persons who did not have complaints recently are more likely to forget to report their earlier contact dermatitis. 

United States). They showed point prevalence rates of... 

Prevalence is the total number of active (existing and new) cases of the disease in a defined population, either during a specified period (period prevalence) or at a specified point in time (point prevalence). The prevalence nosocomial infection rate is calculated simply by dividing the number of active nosocomial infections in patients surveyed by the number of patients surveyed. Because nosocomial pneumonias occur relatively infrequently, the period chosen for surveillance must be large enough for an adequate estimation of a hospital s prevalence rate and usually varies depending on the number of occupied beds in a hospital. In addition, these rates require risk adjustment, which is currently not available for interhospital comparison of prevalence rates. 

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