A positive predictive value of a test depends on the prevalence of the tested disease.
What if the disease was a growing pandemic like COVID-19?
Should we specify a local prevalence, or depend on the global prevalence?
And how will this affect the integrity of our results in trying to build a predictive model?
Thank you.
PPV is very common all over the world.In 2005 there an estimated 500,00 cases cervical cancer world wide and 250,000 related deaths.cervical cancer incidence rates vary from 1 to 50 per 100,000 females rates are higher in latin ,American ,caribbean,and sub-saharan Africa,melanesia ,south central and south east Asia.
Predictive values are valuable resources to understand and interpret the diagnostic test outcome from a patient perspective.
PPV is valuable when the prevalence or the likelihood of the disease is variable from one setting to another (i.e. community setting vs. hospital setting). In the time of the pandemic, it is difficult to accurately estimate the true prevalence of the disease in the population. Predictive values can still be used in the pandemic.
For example, a suspected case living in a family (with no COVID-19 cases) who present to me with a negative PCR is more likely to be COVID-19 free than a physician who works in direct contact with COVID-19 patients on a daily basis and has a negative PCR.
Again the scenario and interpretation here depend on the country, prevalence rates, and infection risks.
Thank you Ahmed Negida ,
Your story inspired me and my friends to form a team and become researchers.
In fact, we've read your model in medical student research and followed something similar.
You and Abdelrahman Abushouk are really inspiring exemplaries for medical students to learn research skills and start generating science.