Eye Health Blog

It has been interesting reading the analysis and opinion around the new Rudd health plan. In fact, I am confident that the commentators have put an order of magnitude more of thought into the plan than the authors of the plan itself. The idea is a flawed diversion destined for failure.

The first reason for this is that there has been as yet no extra money allocated to the health system. The entire premise is that an equal number of bureaucrats (presumably the existing ones relocated) will somehow magically extract new efficiencies from the same health dollar. Efficiencies that these same bureaucrats have been unable to think of or implement until now. It is analogous to Victoria hoping that all the public transport woes will be solved by covering over the name Connex with stickers that say Metro.

The second reason is the cowardice that keeps the States ultimately responsible for health delivery. The states have to underwrite the so called efficient price. The states have to negotiate enterprise agreements with the staff of the hospital. It seems to me this is a recipe for more rather than less blame shifting. The courageous alternative would be for all public hospitals to be run by the Commonwealth so that failures and blame would unambiguously rest there.

The third reason is that this plan lacks any new methods of rationing of healthcare. Although rationing is one of those words which must remain unspoken, the central problem of economics is after all the reconciliation of unlimited wants against limited supply. It is patently ridiculous that for many elective operations there exists no agreed threshold for surgery and no prioritization of those waiting according to the magnitude or impact of their symptoms. Admitting the fact that expectations will always exceed demand and having a rational debate about this point is essential to the design of a new system.

Caution is recommended in interpreting what is meant by independent - as in independently determined efficient price. This is from the same crowd that think that Fair Work Australia and the Henry review of taxation are exemplars of independence.

The cynical view is that this is a political exercise designed to fail and to leave the excuse that “we would have fixed all this if only the (State Bureaucrats / Liberal Party / Greedy Ophthalmologists / insert your villain of the day) had let us so you can’t blame us - we tried and its not our fault.

BEES forums are now live on http://www.bees.net.au/forum/phpBB3

One of the key things that ethics committees look at when determining whether to accept a research proposal is the statistical justification. The ethical issue is twofold:

1. Is an excessive number of subjects being requested while ;
2. Is the number of subjects sufficient to reasonably expect to get a significant result.

Doing the statistical analysis for the application can be daunting and confusing for a prospective researcher. The online resources are often not very good either. I have found the easiest program to use for these calculations to be sigmastat. It is, however, quite expensive even for an academic license.

Fortunately, there is a free alternative. The free software package
r

can do all the power calculations for you and is available for windows, mac and even linux. It is not the most user friendly package so this guide is designed to help you use the program for your ethics commitee application.

First decide what test you are going to use.

1. For two groups with a continuous (assume normally distributed ) variable - for example the length of male vs female elephant tails - use a t test. You must also decide whether the test needs to consider whether the first group is larger or the same as the second (a one tailed test) or whether the first group could be larger, smaller or the same as the second (a two tailed test)
2. For more than one group with a continuous (assume normally distributed) variable - for example the average height of asians, africans and north americans - use an ANOVA
3. For the comparison of success or failure as a proportion of two or more groups - for example the proportion of women who conceived using a fertility treatment - use a test of proportions

Let’s consider these one by one

1. T-test
   work out your parameters - in this example assume that the standard deviation of the elephant tails is 20% and we hypothesize that the male ones will on average be 40% greater.

   Fire up R and type ?power.t.test this will display the help screen

   In this case the command to get your analysis is

   power.t.test(delta=0.4,sd=0.2,sig.level=0.05,power=0.8)

   this gives you 5 subjects per group

   if you want the one tailed option (ie we are only testing whether male tails are longer male tails being significantly shorter is not a possibility)- you need
   power.t.test(delta=0.4,sd=0.2,sig.level=0.05,power=0.8,alternative=”one.sided”)

2. ANOVA test

   This is the most tricky of the three. We first need to know our expected difference in the means and the standard deviations of the groups - is this example let’s say standard deviation again is 20% and we are looking for a difference in the means of 40%.

   The first step is to work out Cohen’s D value - this is the difference in the means divided by the standard deviation - in this case 2.0

   The next step is to work out Cohen’s effect size - this is given by

   

   so in our example we have f = 0.707

   now within r we need to load an additional module so start r and type

   require(pwr)

   then ?pwr.anova.test for the help screen

   and for our power calculation

   pwr.anova.test(k=6,f=0.707,sig.level=0.05,power=0.8)

   which gives us 6 subjects per group (you can’t use fractions of a subject)

3. Test of Proportions
   this one is fairly easy - for this example let’s say that we guess that 80% of women on a fertility treatment will conceive and of those on the placebo 10% will conceive

   In R type

   ?power.prop.test

   and for our example

   power.prop.test(p1=0.8,p2=0.1,sig.level=0.05,power=0.8)

   which gives us 7 per group

I hope this is useful and i might revise this with some more tricky power calculations later. Any experts are welcome to comment

You know if a proposed measure is opposed by both the coalition and the greens that there is a problem with it. You can understand the proposed change to the cataract rebate better if you look at it as a test case to see how much the Government can get away with beating up the doctors and patients of private medicine. I am sure there will be some negotiated deal eventually - maybe cutting the rebate by 25% but this is a prelude to cutting all rebates for all procedures and consultations by a similar amount.

The justification for a 50% cut is nonsense as I have previously written. Faced with the fact, all the Minister can come up with is to insult the profession. Minister, I know you have a dystopian vision of a health care system without any doctors but really - you should be able to do better than this. Claims of ophthalmologists with incomes of $500 000 per year or more conveniently ignore the fact that this is gross practice income. The most efficient practices cost 50% or more to run. There is about 1 hour of non-medical time spent on every consultation and rents, insurance, capital, computers, utilities etc are all going up.

The intolerable situation of patients now being faced with thousands of dollars out of pocket or their operations being cancelled for months must not be allowed to stand. Bouquets to the Greens and Brickbats to our irrational Minister

The ALP ’solution’ to the problem of overcrowding of the Christmas Island immigration facility of installing bunk beds and portaloos in the recreation facilities is very cost effective. In fact, we might expect our health minister to broaden this strategy to our public hospitals and install bunk beds and portaloos in the hospital corridors as a remedy to the recently reported overcrowding of these facilities.

As the implementation date for the cut to the medicare rebate for cataract surgery (1 November 2009) approaches - one might speculate how the matter may play out. This is obviously important for those agencies which are involved with the provision of cataract surgery.

A 50% cut in the fee attaching to a service is obviously an extreme measure. It might have been hoped that it was an ambit proposal and that possibility although unlikely probably still exists. A cut of say 10-20% might have been allowed through with some grumbling of patients and doctors but no sensible person would expect a 50% cut to not have serious implications and face serious resistance. So what options might be available to the profession?

The first option is to grin and bear it - cutting the fee to patients by the suggested 50%. The chance of this happening is extremely small

The second option is to pass on the full impact to the patient - insured patients will face gaps of up to $300 and uninsured patients will face increased out of pocket costs. For many patients who require surgery on both eyes the increase may force them to seek public surgery when they previously would have paid for their own surgery. This may not work out either for reasons elaborated below. This is the most likely outcome but the cause for the fee increase will be explained in detail and the blame attributed every time informed financial consent is obtained.

It is unlikely when public waiting lists expand that those ophthalmologists working in public will be sympathetic to increasing their commitment or productivity at public hospitals. For most such ophthalmologists, the state Government is ALP - a party which has just defamed the profession on its website. More extreme action would be for all public ophthalmologists to resign from the public health service. Such action would not be a secondary boycott or industrial action and has precedent to those who have studied the interaction between the medical profession and Governments of both persuasions. Such action would of course be catastrophic to the public cataract surgical waiting lists - not to mention the provision of emergency ophthalmology services.

Medical conscription is not a possible response as it is forbidden by the constitution. It will be interesting to see how the end-game plays out

I recently had a sobering learning experience. I wanted to change the name of an XP workstation on the windows 2003 domain to preserve printer mapping that was within each user profile. (That in itself was a mistake and it would have been better to use the poorly documented and mostly unknown ‘add machine printer’ via PrintUIEntry but more on that in a future post). Hopefully anyone considering a similar thing is reading this BEFORE the change rather than after he or she is in serious trouble.

Here are some tips to avoid disaster :

It is a big mistake to try and save one reboot be renaming it in one go. The AD information may get scrambled and there is a good chance you wont be able to login at all - except to the machine itself with the local administrator password.

I hope these tips save someone some grief

Superficially, the idea to have a new health card to which patients control the access seems attractive. There are a number of significant flaws with the proposal which render it potentially dangerous.

Doctors tend to treat lists as authoritative. That is, if the doctor retrieves a list of medications from the card, he or she will likely conclude that it is accurate (what is the point if it is not accurate). If the patient has selectively allowed access to the card - say to his or her GP but not the psychiatrist, or has allowed access on selective occasions, then the list will not be correct. One might conclude that the absence of a medication on the list means that the patient is not on that medication, or the fact that it is on the list means that they are still on that medication or still at that dose. The potential adverse consequences of mistakes are obvious Similarly, one might conclude that the list of allergies is complete and that the fact that say, penicillin is not on the list means there is no allergy to that drug. One should always check but the temptation is there to not do so.

Further, many doctors have not computerized their medical records so will not have access to the technology. It is less of an issue that such a doctor cannot read the record, more of an issue that he or she cannot add important information.

The only way that this proposal will be a success is if it is compulsory for every doctor, pharmacist and hospital to use it, the Government shoulders the cost of integration into existing software, subsidizes the in-practice hardware and makes it part of the Medicare Card.

Otherwise, this will add to the $1bn already spent on Electronic Health Records in this country with nearly nothing to show for it.

One of the factors missed by most commentators in relation to the private health insurance rebate changes in Australia is the problems with its administration. Currently the rebate is taken off the premium before it is charged to the client, making it that much more affordable. For example a $3000 annual premium becomes only a payable $2100.

Of course, the insurers will not know how much rebate a client is entitled to so will need to charge the full $3000 with a rebate in the annual tax return - this is a significant cash flow problem for those entitled to the rebate who have found their premiums have (at least until tax time) gone up by 42%

The alternative is the shambolic “estimation of taxable income” and rebates which may need to be repaid if the estimate is incorrect and the liability borne by ??

It would all be a disaster. Let’s hope that it’s defeated.

Astigmatism is a very difficult concept to explain to students and patients. There are no good webpage references on the combination of different spherocylinder lenses. Understanding how they add is however important in understanding how the Jackson Cross Cylinder works and also in understanding how astigmatic changes come about with surgery.

At Broadmeadows Eye and Ear Specialists we have the Holladay software for analysing surgical astigmatism which is allowing each of our doctors to form their own database parameters for the optimized management of astigmatism.

As a teaching tool, i have developed an online astigmatism calculator - it can add and subtract spherocylindrical lenses. It is still in beta form and not 100% accurate but will help in the understanding of astigmatism. Please feel free to leave suggestions or drop me a line for the source code