This is the second part of a two-part article on drug effectiveness: Part I | Part II

Let's assume that a credible, third-party source with therapeutic, statistical and analytic expertise has established definitive evidence that one drug is better than others in treating a particular disease in certain types of patients. They publish the treatment guidelines in a peer-reviewed reputable medical journal, issue press releases and present their findings at relevant medical meetings.

Would the guidelines be followed? You would think so, but treatment guidelines and best practices are slow to be adopted, regardless of how convincing and definitive they might be. This is especially true for drug treatments. A lot of competing forces work against adoption of treatment guidelines of any type.

You would think conclusive comparative effectiveness studies and specific best-practice guidelines would be the foundation for treating patients with the disease in question. Unfortunately, they either don't exist, or those that do exist don't appear to be sufficiently credible to convince practicing physicians to follow them.

First, individual physicians have the right to determine which drugs they will prescribe for a particular patient. At the same time, despite continuing medical education requirements, not all physicians stay current with available new treatments or practice guidelines. And, while they may never admit it, many probably feel they don't need any help determining what might be best for their patients.

Similarly, many physicians might not agree with the guidelines. They might feel their personal experience isn't captured, and therefore they use their bias as justification for ignoring these recommendations. After all, it's what they went to school to do and they have "X" number of years of experience, so thanks, but no thanks, for the guidelines.

Perhaps these physicians have good reason to be skeptical of treatment guidelines, especially as they relate to drugs. Some guidelines have been discredited as being encouraged, supported financially and influenced by drug companies. Drug treatment guidelines also tend to be equivocal with sufficient numbers of caveats and patient-specific exceptions to provide the average practicing physician plenty of excuses to ignore them entirely.

So therein lays the irony. Without clinically-relevant, credible comparative effectiveness data, how can physicians, healthcare providers and insurance companies determine which drug will work best for your medical condition?

The only conclusion that can be asserted from this discussion is that we are all drug treatment guinea pigs. Trial and error. The drug prescribed for you might work, might not. Might not have side effects, but you might. Might be safe, might not. You might get the best drug treatment you need, but then again, you might not.

Unfortunately, drug companies like it this way as all patients with a particular diagnosis become potential customers. Whether a drug company has the best treatment or not, all patients with the indicated diagnosis become potential customers. Physicians, healthcare providers and insurers just accept this uncertainty, which provides them plenty of flexibility in choice.

For physicians, it might be flexibility to prescribe their favorite without having to justify their choice. For healthcare providers and insurance companies, it might be flexibility to leverage formulary inclusions or exclusions based on price.

The only group that doesn't benefit from the lack of comparative effectiveness data to support a drug choice are the patients, who in most cases, would like to be treated with the best drug available for their conditions.