Questions
1. Would you pay $1000/month for a drug that guaranteed an increase in your UPDRS score of 4.7 points?
2. Would you undergo brain surgery for an average increase in your six year survival rate of 10%?
3. Would you exercise a hour per day if it led to an average 23.9% reduction in your levodopa equivalent daily dose (LEDD) ?
4. Would you take this supplement if it increased your daily "on" time by 21 minutes?
5. Would you choose transcranial magnetic stimulation if it had a significant effect on your walking ability?
6. Would you move house if on average it decreased your side to side tap score by 8.8%?
Measuring metrics
I'm a great believer in the benefits of taking measurements. Good measurements can lead to improvement in the performance of almost any system, be it a company, a sports team or, as it applies here, the quality of life of PwP.
Without metrics you are unsure whether an action, a new drug for instance, has led to an improvement.
So, my basic instinct is that measurement is good ... except that is when it's bad.
Metrics for PwP should convey meaning to PwP.
Metrics for PwP should be comparable, one with another.
Metrics for PwP should be congruent with goals.
Get the metric wrong and billions of dollars of research grants, pharmaceutical costs and surgical fees gets sub-optimally spent.
What metrics would you choose to best represent your PD?
Answers
1. No. A trick question. Low UPDRS scores are good. So paying to have them increased is crazy. Even if it had been the other way around, a decrease rather than an increase, what does 4.7 points mean? 4.7 out of what? Totalling the scores from parts 1 to 4 of the UPDRS gives a score ranging from 0, no disability, to 199, total disability [1]. But are all points worth the same (is there linearity)?
2. Don't know. Everything else being equal an increase in survival rate is good. But, perhaps, it's not equal. For instance, if a side effect is more falls. Also be careful of the 10% increase. Taken literally this would take someone's survival rate from, say, 50 to 55%. But, it's easy to mistakenly read the 10% as a 10 percentage point increase, taking 50 to 60%.
3. Don't know. The implication, but only that, is that your condition has improved to the extent that a lower LEDD is required for the same quality of life. That's good, but what PwP are looking for is a higher QOL? There is also the suggestion, but no more than that, that the rate of progression is slowed.
4. Don't know. At least for me, not all "on" time is equal. The intensity of the transition from "on" to "off" is particularly important.
5. Don't know. Here the key word is "significant". It can mean significant by magnitude, in the sense that I can now walk 10 miles in a day whereas previously I could only manage 1 mile. It can also mean statistically significant in the sense that the cohort's average went from 1 to 1.1 mile per day and that was unlikely to have occurred by chance. What we are looking for is significant significance.
6. No. A trick question. Low tap scores are bad. Something that made them worse is a bad idea.
Reference
[1]
http://www.epda.eu.com/en/parkinsons...-scales/updrs/
John