Sunday, 1 July 2012

Spreadsheet and Graph to monitor my progression

In my twitter @sgpozsterboy, I promised to share how I monitored my progression before and after starting medication.

Okay, please spare this geek some time and carry on reading. For the following, I used Microsoft Excel. What I did was to put all the data I have from every blood test into a table with the dates (blurred to protect my identity, yes I am that careful) and other necessary data. You will notice that I have the heading "days". I made the first day I took my blood test as "day 1" and subsequently started counting the days of the other tests from this date. The reason for doing this is to allow a graph to be plotted to gauge roughly when to start my medication.

I then plotted a graph with the horizontal axis being "no of days" and the vertical axis "CD4 counts". I told myself that I will start to seriously consider when to start my medication when my CD4 cells falls around "200 - 350" but NOT below "200".

After you get the plot in, I got the program to plot in the "trendline" and add in the equation. There is an assumption here that the decline of CD4 cells is linear, meaning it will continue to fall at a same uniform rate. In other words, IF every month it falls 10, then I am assuming that it will continue to fall 10 per month. Of course there is not guarantee that it will continue to fall at the same rate. CD4 rates are known to fluctuate and may drop suddenly drastically especially when one is ill with common illness so I knew I had to be careful using the data here.

So once I had the trendline and equation which in this case is 

y = -0.0836x + 458.33

So, once I had this equation, I did a simple substitution and I got a rough guage of when I will need to start medication. For eg, let's say I tell myself to start medication when my CD4 drops to 350. What I will do is to substitute "y" with 350. (Recall, the y axis or vertical axis represents CD4 counts). By solving the equation for x, I will get the number of days and from there I can calculate how much more time I have.

350 = -0.0836x + 458.33
350 - 458.33 = -0.0836x
-108.33 = -0.0836x
x = -108.33 / -0.0836
x = 1295.81

So roughly about 1295.81 days from the first day of test, I should consider starting my medication.

HEY! IS THERE ANYTHING WRONG WITH MY CALCULATION? If you look at the table, 1295th day was up LONG AGO. Yes, if you've been reading carefully, you will notice that my last few test results had increase in CD4 counts (I started medication) and because of this, it affected the equation. The graph with all the downward trend was before I started medication. After I started medication, you can see that the CD4 immediately shot up within 3 months.

Things to note:

The school of thought regarding when to start treatment has changed quite drastically within the last year. Right now, clinicians think that is best to start immediately after one is diagnosed. The reason is that once your CD4 cells go below a certain level, it is really quite hard to get it back up again and may require a longer time. Another way to think of it is to think of taking medication early has a preventive measure to protecting your immune system before HIV affects it too much. However, HIV meds are heavy on the liver and kidneys as well as on the pocket especially when you are a student. (I recently found out that first line meds are available at less than $300 per month.)

Medication is recommended also for couples whom one is HIV+ and one who is not. Recent findings show that this is reduce transmission rates. That being said, it doesn't mean you can go barebacking with your HIV+ bf if you're on medication. It just means that the chances are lowered. It doesn't mean transmission cannot happen. Don't forget, HIV medications are only effective against HIV. Other nasty infections are still possible. Effective condom use along with close adherence to the medication regiment is currently our best weapon against the spread of HIV.

The information here is meant to let you all know that one can be control of one's HIV condition. Always discuss with your doctor your concerns.

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