AAPA

Overview

Table 1 presents the AAPA Division of Data Services and Statistics' estimates of the total number of visits made to PAs for each of 25 major types of disorders in 2001.

Table 1. Estimated Number of Visits to PAs in 2001

AIDS/HIV-Related Problems Allergic Disorders Alzheimer's Disease Asthma Cancer Congestive Heart Failure Contraception COPD Depression/Anxiety Disorders Dermatitis/Skin Disorders Diabetes Dyslipidemia Erectile Dysfunction Gastrointestinal Disorders & Infections Gynecological Disorders & Infections Headache (including Migraine) Hypertension Musculoskeletal Disorders/Injuries Obesity Management Osteoporosis Overactive Bladder Pain Management Respiratory/ENT Infections Sleep Disorders Urinary Infections

1,229,474 12,452,535 2,241,735 8,629,859 4,685,057 5,929,693 6,041,205 6,869,782 9,848,048 9,835,346 10,161,499 8,885,422 2,335,732 9,789,942 7,679,276 7,982,241 12,109,935 15,050,114 4,293,342 3,717,364 2,744,981 10,536,297 15,939,658 3,287,560 7,684,877

Methodology

As part of the 2002 AAPA Market Research Survey (MRS) performed at AAPA's 30th Annual Physician Assistant Conference in May 2002, we asked a convenience sample of about 2500 PAs to estimate the number of visits made to them in a typical week for each of 25 disorders/conditions/services.  The specialty distribution of the respondents to the 2002 MRS is, however, slightly different from the distribution estimated for all PAs in clinical practice.  Since specialty is likely to correspond with the number of visits made for particular disorders, we weighted the MRS data to adjust for this difference when estimating the number of visits made to all PAs for each of the 25 disorders during the year.

In summary, to generate estimates of the total number of visits to all PAs for each disorder, we performed the following calculations, which are described in greater detail below:

1. Calculated the Means --First, we calculated the mean number of patient visits for each disorder that were made to a PA working in each major specialty in a typical week.
2. Determined the Annual Total for Each Major Specialty --Next we multiplied the mean visits per week by the estimated total number of weeks worked per year by the PAs in each major specialty group.
3. Estimated the Overall Total --Finally, we summed the totals estimated for each major specialty group.

Note: We adjusted for the specialty distribution of the MRS respondents and confirmed that the work status distribution (percent full-time) observed for the MRS respondents was comparable to the distribution estimated for the total population of clinically practicing PAs.  Still, to develop our estimates we have to accept one untestable assumption: the practices of the self-selected MRS respondents in each major specialty group were comparable to those of other PAs in that major specialty group.

Determining the Means

To determine the mean number of visits made to a PA in each major specialty group during a typical week for each disorder, we needed to prepare the MRS data on the number of visits per week, as they were not collected as continuous data.  Instead they were collected in the following categories:

a = 0 visits
b = 1 visit
c = 2 visits
d = 3 visits
e = 4 visits
f = 5-6 visits
g = 7-8 visits
h = 9-10 visits
i = 11-15 visits
j = 16-20 visits
k = 20 visits

The specific preparations involved converting the responses of those individuals who cited a category representing other than a single number into a point estimate.  Specifically, to the respondents who cited one of the finite categories, we assigned the midpoint of the range represented by the category selected.  Similarly, to the respondents who cited the final unbounded category representing "21 or more patients", we assigned the value of 21.  Following the recoding of data, we produced a simple mean for the number of patients treated for each disorder by each of the 14 major specialty groups of PAs.

Calculating the Annual Total for Each Specialty

To estimate the total number of visits made to PAs in each major specialty group during the year for each disorder, we multiplied the mean number of visits per week by the total number of weeks worked by the PAs practicing each specialty.  The total number of work weeks for each specialty was projected to equal the weighted average of two estimates: one for new graduates, whom we assumed worked on average 24 weeks per year, and one for other graduates whom we assumed worked 48 weeks per year.  Table 2 presents our estimates of the total number of clinically practicing PAs (on a full or part-time basis, new graduates and other PAs) in each of the 14 major specialty groups in 2001.  The process used in producing these estimates is discussed in detail in the AAPA Information Update titled: Projected Number of PAs in Clinical Practice as of January 1, 2002

Table 2.  Estimated Number of Clinically Practicing PAs by Specialty as of December 31, 2001

All Specialties Family Practice General Internal Medicine Internal Medicine Cardiology Internal Medicine Other Obstetrics/Gynecology Emergency Medicine General Pediatrics Pediatric Subspecialty General Surgery Surgery CVT Surgery Orthopedic Surgery Other Occupational Medicine Other

42708 15650 3991 1172 2481 1105 4783 1268 691 799 1420 2470 1948 1594 3336

Estimating the Overall Total

By summing the estimates produced for the 14 major specialty groups, we estimated the total number of patients treated for each disorder by PAs in 2001.

Findings

Table 1 presents our estimates of the total number of visits made to all clinically practicing PAs for the 25 disorders during 2001.  Estimates of the number of visits made to the PAs in each major specialty group for each of the disorders during 2001 is shown in Table 3.

Limitations

These estimates should be used cautiously as the data are limited in a number of ways.  First and foremost, the information representing the number of visits for each disorder per week was not collected as continuous data.  The use of midpoints to recode the responses associated with the categories representing finite ranges probably overestimates the number of visits for any disorder; conversely, the use of minimum values to recode the responses associated with the unbounded category underestimates the number of visits for any disorder.  It is impossible to gauge the net effect of these two procedures on the estimates.   In addition, it is impossible to know how the seasonal prevalence of some disorders affected the respondents' weekly projections made in May.

Table 3. Number of Patients Treated for Select Disorders in 2001 by Major Specialty Group*

Disorder	Family Practice	Internal Medicine General	Internal Medicine Cardiology	Internal Medicine Other	Ob/Gyn	Emergency Medicine	Pediatrics General	Pediatric Subspecialties
AIDS/HIV-Related Problems	159,832	263,940	13,852	250,300	38,047	282,758	13,847	6,299
Allergic Disorders	7,258,249	1,394,135	56,598	266,506	83,938	1,603,821	179,702	406,273
Alzheimer's Disease	715,552	512,707	65,118	152,161	6,276	448,545	7,954	11,338
Asthma	4,211,581	968,820	86,500	254,150	66,680	1,738,088	107,947	342,970
Cancer	903,003	447,522	59,337	516,923	79,231	524,491	23,918	6,929
Congestive heart Failure	1,864,880	795,730	712,318	303,421	10,983	1,144,006	39,969	3,149
Contraception	4,028,812	410,634	11,390	54,915	790,353	377,462	25,177	32,439
COPD	2,911,198	1,133,248	264,734	339,436	22,750	1,263,366	81,452	1,890
Depression/Anxiety Disorders	5,244,919	1,360,059	111,742	476,986	224,358	1,059,569	102,282	65,823
Dermatitis/Skin Disorders	4,858,573	1,150,423	63,597	340,380	102,373	1,329,488	173,722	320,924
Diabetes	4,798,290	1,640,181	381,886	580,732	131,399	1,144,520	97,247	34,958
Dyslipidemia	4,786,343	1,433,367	712,976	420,018	35,301	426,664	108,891	17,952
Erectile dysfunction	1,122,825	346,674	71,813	163,382	4,707	207,671	19,727	630
Gastrointestinal Disorders & Infections	4,109,887	1,176,027	117,761	794,016	82,860	1,731,164	130,292	274,628
Gynecological Disorders & Infections	4,021,891	556,217	32,255	141,844	956,845	1,394,646	54,980	47,871
Headache (Including Migraine)	3,741,966	872,556	87,027	314,635	129,830	1,534,667	116,458	131,645
Hypertention	5,904,755	1,888,591	734,034	608,145	126,262	1,148,035	169,986	17,322
Musculoskeletal Disorders/Injuries	5,860,090	1,421,626	90,852	400,365	57,466	2,769,254	813,817	198,727
Obesity Management	2,222,684	678,415	212,091	191,067	128,261	191,119	77,420	97,632
Osteoporosis	1,541,539	586,967	65,876	274,993	205,923	199,467	35,635	-
Overactive Bladder	1,203,309	469,055	39,554	123,178	165,915	225,506	16,227	5,669
Pain Management	3,369,087	1,083,944	84,345	607,125	145,403	1,834,175	341,150	28,590
Respiratory/ENT Infections	9,052,160	1,691,964	134,236	467,287	94,412	2,618,414	186,626	496,346
Sleep Disorders	1,486,897	512,786	80,043	315,716	39,040	233,297	36,996	31,809
Urinary Infections	3,645,597	895,765	52,947	274,460	356,149	1,470,942	85,288	111,489

Disorder	Surgery General	Surgery CVT	Surgery Orthopedics	Surgery Other	Occupational Medicine	Other	All Specialties
AIDS/HIV-Related Problems	38,949	23,215	8,717	7,813	21,070	100,835	1,229,474
Allergic Disorders	217,851	40,178	37,154	16,825	147,699	743,604	12,452,535
Alzheimer's Disease	4,621	20,310	48,567	12,954	27,221	208,412	2,241,735
Asthma	199,631	54,889	125,482	14,443	91,911	366,766	8,629,859
Cancer	35,648	502,169	194,912	34,509	505,690	850,774	4,685,057
Congestive heart Failure	39,939	97,575	660,635	15,340	56,673	185,075	5,929,693
Contraception	91,737	8,504	59,194	2,707	36,812	111,069	6,041,205
COPD	42,682	88,869	360,834	19,100	82,155	258,069	6,869,782
Depression/Anxiety Disorders	105,625	61,317	130,354	34,475	115,800	754,739	9,848,048
Dermatitis/Skin Disorders	186,860	114,353	100,757	35,225	126,552	932,119	9,835,346
Diabetes	65,199	160,312	494,337	72,808	141,093	418,537	10,161,499
Dyslipidemia	39,279	78,414	511,198	19,486	68,911	226,622	8,885,422
Erectile dysfunction	9,746	26,050	40,303	1,799	129,292	191,115	2,335,732
Gastrointestinal Disorders & Infections	188,204	519,707	115,928	25,116	134,231	390,121	9,789,942
Gynecological Disorders & Infections	83,012	107,601	15,647	18,886	67,789	179,794	7,679,276
Headache (Including Migraine)	86,260	34,880	119,750	32,786	215,487	564,293	7,982,241
Hypertention	50,412	145,501	702,777	74,245	130,979	408,890	12,109,935
Musculoskeletal Disorders/Injuries	168,413	160,312	139,860	1,690,807	420,326	858,198	15,050,114
Obesity Management	60,734	94,926	92,145	82,417	64,980	99,450	4,293,342
Osteoporosis	14,854	30,857	41,725	382,339	58,137	279,052	3,717,364
Overactive Bladder	31,027	29,140	71,340	18,259	166,190	180,611	2,744,981
Pain Management	99,746	313,296	518,267	702,261	457,783	951,127	10,536,297
Respiratory/ENT Infections	295,065	76,534	140,770	18,524	190,598	476,723	15,939,658
Sleep Disorders	45,184	29,950	56,705	17,296	75,878	325,964	3,287,560
Urinary Infections	94,774	81,227	124,364	24,765	180,887	286,223	7,684,877

*PAs are assigned to the specialty in which they spend the most time providing clinical services for their primary employer. Note, some PAs practice multiple specialties and roughly 20% hold multiple clinical jobs.